成排立管的外形尺寸控制

在集气站单井总机关安装时,为保证其外形尺寸及精度,本文详细论述了不同安装过程对总机关安装外形尺寸精度的影响,介绍了能改善和解决集气站单井总机关安装时,外形尺寸不好控制的问题。     

一种新型液体硬化剂的研究

通过正交试验研制出了新型液体硬化剂,用此配制的水玻璃自硬砂,具有较高的24h 强度和较低的残留强度。此种硬化剂价格低、无毒无味。     

铸钢壳体砂型铸造工艺数值模拟及优化

为了减少壳体在砂型铸造过程中所产生的气孔、夹杂、浇不足及缩孔、缩松等缺陷,提高壳体铸件的合格率,依据壳体铸件的工艺特点,设计了3种浇注工艺方案,利用计算机模拟软件研究了浇注温度、浇注速度对砂型铸造壳体充型、凝固过程及铸件孔隙体积的影响;采用正交试验的方法研究了第3种工艺方案浇注温度、浇注速度对壳体铸件孔隙体积的影响,最后按照优选出的浇注温度、浇注速度工艺参数进行生产验证。研究结果表明：第1种和第2种工艺方案在铸件上方均出现了浇不足铸造缺陷,第3种工艺方案的缩孔、缩松缺陷体积明显减少,方案较好;优选出的工艺参数为浇注温度1 560 ℃,浇注速度1.6 m/s,工艺参数下壳体铸件孔隙体积最小,为1.416 cm³,铸件合格率为96%,并且铸件的组织和性能均满足要求。所提第3种方案可缩短试制周期,降低生产成本,提高经济效益,研究可为壳体类铸钢件砂型铸造工艺的设计提供参考依据。     

盾构穿越全断面砂层及钙质结核区关键施工技术

随着盾构技术的日益成熟,盾构区间施工时,遇到地层也越来越多样。本文重点探讨了在盾构区间施工中,为了穿越全断面砂层及钙质结核区,制定一整套客观科学的技术措施。     

NONLINEAR FORECASTING OF THE GOLD MINER SPREAD: AN APPLICATION OF CORRELATION FILTERS

This paper models and forecasts the Gold Miner Spread from 23 May 2006 to 30 June 2011. The Gold Miner Spread acts as a suitable performance indicator for the relationship between physical gold and US gold equity. The contribution of this investigation is twofold. First, the accuracy of each model is evaluated from a statistical perspective. Second, various forecasting methodologies are then applied to trade the spread. Trading models include an ARMA (12,12) model, a cointegration model, a multilayer perceptron neural network (NN), a particle swarm optimization radial basis function NN and a genetic programming algorithm (GPA). Results obtained from an out‐of‐sample trading simulation validate the in‐sample back test as the GPA model produced the highest risk‐adjusted returns. Correlation filters are also applied to enhance performance and, as a consequence, volatility is reduced by 5%, on average, while returns are improved between 2.54% and 8.11% across five of the six models. Copyright © 2013 John Wiley & Sons, Ltd.     

基于径向基函数网络的工程项目风险评估研究

工程项目风险评估是工程项目风险管理中的一个重要环节,受到了人们特别的重视。本文通过考虑输入———输出扩展矢量的方式改进了应用广泛的HCM算法。评估实例表明改进的HCM算法可以获得更好的评估效果,提升了RBF网络评估工具的价值。     

Penalized Regression with Ordinal Predictors

Ordered categorial predictors are a common case in regression modelling. In contrast to the case of ordinal response variables, ordinal predictors have been largely neglected in the literature. In this paper, existing methods are reviewed and the use of penalized regression techniques is proposed. Based on dummy coding two types of penalization are explicitly developed; the first imposes a difference penalty, the second is a ridge type refitting procedure. Also a Bayesian motivation is provided. The concept is generalized to the case of non-normal outcomes within the framework of generalized linear models by applying penalized likelihood estimation. Simulation studies and real world data serve for illustration and to compare the approaches to methods often seen in practice, namely simple linear regression on the group labels and pure dummy coding. Especially the proposed difference penalty turns out to be highly competitive.     

致密砂岩气藏开发阶段地层研究尺度

随着油气田开发的深入，油气藏描述需要更加精细的地层划分对比方案，但需要讨论研究尺度的合理性。以新召东区致密砂岩气藏为例，通过对地质特征、开采现状和地震条件的统计分析，认为需要分析地震资料品质、沉积相类型和砂体可分性等3方面因素。地震资料品质考查的是地震能够分辨的单砂体厚度，沉积相类型研究的是砂体发育程度及连续性，砂体可分性揭示的是小层内测井可识别的单砂体个数。研究成果可为开发阶段地层研究尺度确定提供借鉴。     

传统屋脊上的文化浅析

中华民族是木文化的民族，寺庙、宫殿建筑是木结构建筑的颠峰代表作：大屋顶、斜坡面、深出檐、高翘角，脊吻、走兽，神奇的传说向世人展示了中华民族建筑文化方面的独特风貌。本文试图从正脊和垂脊上的吻和兽来探寻传统屋脊上的文化。     

静压管桩穿过砂夹层的几种有效辅助措施

根据预应力高强混凝土管桩基础的工程设计及施工,分析、探讨静压管桩穿过砂夹层的几种有效辅助措施,为科学合理应用预应力高强混凝土管桩基础提供参考.