K-230B镗床万向护板的设计

介绍了大型机床地坑移动盖板的一般设计思想,根据机床原有功能和结构特点,设计兼顾防尘防屑和美观大方两大特点的活动盖板,为同类设计提供一些参考。     

Genetic algorithms for symbolic clustering

This paper introduces a novel methodology for clustering of symbolic objects by making use of Genetic Algorithms (GAs). GAs are a family of computational models inspired by evolution. These algorithms encode potential solutions to specific problems on simple chromosome-like data structures and apply recombination operators to these structures so as to preserve critical information. A new type of representation for chromosome structure is presented here along with a new method for mutation. The efficacy of the proposed method is examined by application to numeric data of known number of classes and also to assertion type of symbolic objects drawn from the domain of fat oil, microcomputers, microprocessors and botany. The validity of the clusters obtained is examined.     

高砂比压裂技术研究

应用由美国ＮＳＩ公司引进的“ｓｔｉｍｐｌａｎ”拟三维压裂设计软件，对影响裂缝内支撑剂铺置浓度的诸因素进行了灰色关联度分析，从中找出了主要的影响因素。并以高砂比压裂的技术指标为依据，研究了在目前压裂工艺水平下，进行高砂比压裂所必须遵循的原则。文中还对国内的高砂比压裂进行了实例分析，进一步论证了文中的观点。     

粗集理论中不相容规则的一种修正算法

粗集理论是继概率论、模糊集、证据理论之后的又一种处理模糊和不确定性知识的数学工具。针对粗集理论在实际应用中常常出现的条件属性相同而决策属性不一致问题，提出了一种修正不相容规则的算法。即从相对错误分类率概念出发，在力求保持原知识分类能力的前提下，通过比较不相容规则的相对错误分类率大小，从而对不相容规则进行修正的算法。并通过雷达分类实例验证了算法的可行性。     

河道堤防老化指标体系评定之浅见

水利工程老化、失修是当前工程不能发挥正常效益的主要原因,建立工程老化指标评价体系是解决该问题的基础工作之一。老化是工程建成后在自然因素和人为活动长期连续的作用下,工程效益衰减、构件功能降低及材料性能逐渐变坏的自然现象。河道堤防以土石为主要材料,应以工程的功能为主建立老化指标体系。依据对工程效益和安全的影响程度,水利工程的综合老化度可分为四级。工程损坏后,在防洪工程运用年度内未能修复称为水利工程失修。解决老化问题主要依靠折旧或大修费,而解决失修问题主要依靠运行管理和维修养护费。     

聚合物驱油田注入与产出聚合物的对比研究

应用美国Millipore切向流超滤系统，建立了超滤浓缩恒重的方法，消除了产出液中盐等杂质的影响，准确测定了见聚油井产出液中聚合物的质量浓度、相对分子质量和水解度。对孤岛油田5口见聚油井注入与产出聚合物进行了对比研究，发现聚合物在注入及地层渗流过程中相对分子质量和水解度发生明显变化，对同时注聚的见聚油井来说，见聚时间越晚、层位越深、井距越大，聚合物在地下受到的降解和水解作用越严重。     

A novel document similarity measure based on earth mover’s distance

In this paper we propose a novel measure based on the earth mover’s distance (EMD) to evaluate document similarity by allowing many-to-many matching between subtopics. First, each document is decomposed into a set of subtopics, and then the EMD is employed to evaluate the similarity between two sets of subtopics for two documents by solving the transportation problem. The proposed measure is an improvement of the previous OM-based measure, which allows only one-to-one matching between subtopics. Experiments have been performed on the TDT3 dataset to evaluate existing similarity measures and the results show that the EMD-based measure outperforms the optimal matching (OM) based measure and all other measures. In addition to the TextTiling algorithm, the sentence clustering algorithm is adopted for document decomposition, and the experimental results show that the proposed EMD-based measure does not rely on the document decomposition algorithm and thus it is more robust than the OM-based measure.     

Kerr介质中"耦合双原子-单模光场"模型的反聚束效应

利用全量子理论,研究了在Kerr介质中,耦合二能级双原子与单模光场相互作用过程的反聚束效应,着重讨论了Kerr介质对场的二阶相干度的影响,并揭示了初始场强及原子间耦合系数的变化与场的二阶相干度的关系。     

PVA平均聚合度波动因素分析及优化控制

针对聚乙烯醇 (PVA)聚合反应过程中 ,平均聚合度波动的实际问题 ,在对聚合反应工艺、反应机理进行理论分析的基础上 ,找出了影响平均聚合度波动的主要因素 ,并逐一分析了对平均聚合度影响的情况 ,在理论和实验基础上找出了在多品种PVA生产中各主要因素变化对平均聚合度变化的规律 ,提出了包括运用先进仪表控制手段在内的优化控制措施和处理办法