Mission segment division of the whole aeroengine loading spectrum based on flight actions

This paper studies on a division method of the whole aeroengine loading spectrum flight mission segment and rotor speed mission segment,which is based on the actual flight actions and related to the flight operations of aeroengine and is suitable for the variable-speed aeroengines such as turbojet and turbofan.Through the research,the aeroengine loading spectrum operation-related mission segments can be divided,which can provide important data basis for the life research on the structures which are sensitive to flight maneuver(such as the main shaft,large gearbox and installation section),lay a foundation for the simulation,compilation and prediction of the whole aeroengine loading spectrum.Firstly,based on the summary of basic flight actions in actual flight,the division of flight mission segment was realized by programming.Moreover,the aeroengine rotor speed mission segments,associated with flight actions and missions,were divided based on the flight mission segment division results.Besides,the efficiency and accuracy of the mission segment division results were verified by adopting measured loading spectrum data.Finally,the characteristics of speed mission segment division results were compared and analyzed in tables and figures.The comparison results show that the characteristics of similar speed mission segments are similar,while the characteristics of different speed mission segments are different.And the shapes of similar mission segments vary to the change of flight actions and operations,which can reflect the operation-related feature of the segments.

一种基于分段加权赋参的厚松散层矿区沉陷预计方法

概率积分法作为一种通用的采煤沉陷预计方法,在厚松散层矿区应用中存在边缘收敛过快、沉陷预计失准等问题,给厚松散层矿区“三下”采煤及环境保护带来了一定的困难。为此,在概率积分法基础上提出了一种基于分段加权赋参的厚松散层矿区沉陷预计方法,将监测点根据工作面位置划分为内、外2个区段,分别获取相应预计参数,利用建立的自适应赋权模型对其预计结果进行加权组合;在此基础上,为提升参数反演精度,分别基于标准粒子群算法和自适应模拟退火粒子群算法进行参数反演研究;同时,为提升赋权模型性能,建立了2种自适应赋权模型进行模型优选。试验结果表明:与概率积分法相比,基于分段加权赋参的沉陷预计方法计算的下沉预计值与实测数据更接近,2种赋权模型计算结果的残差平方和分别为0.0071 m^(2)、0.0058 m^(2),小于概率积分法的0.0203 m^(2);2种赋权函数模型相比,模型2精度更高、效果更好;相同条件下,自适应模拟退火粒子群算法精度优于标准粒子群算法。试验结果验证了矿区分区段预计的可行性,反映出该方法能够有效解决概率积分法在厚松散层矿区应用中边缘收敛过快的问题,对厚松散层矿区的沉陷预计有一定的参考意义。

Application of cluster analysis to preventive maintenance scheme design of pavement

To quantitatively identify the maintenance demand for each highway segments in the pavement maintenance scheme design,a mathematical model of uniform segment division was established and an approach of applying cluster analysis theory to the uniform segment division and evaluation of pavement maintenance demand was proposed.The actual maintenance project of a highway carried out in Guangdong province was cited as an example to demonstrate the validity of the proposed method.It is proved that the cluster analysis can eliminate human factors in classification without being constrained by the quantities of samples,considering multiple pavement distress indexes and the continuity of samples.Thus it is evident that cluster analysis is an efficient analytical tool in uniform segment division and evaluation of maintenance demand.

分级分区护理在急性ST段抬高心肌梗死患者急救中的应用

目的 探讨分级分区护理在急性ST段抬高心肌梗死患者急救中的应用效果。方法 将2017年6月至2018年6月我院收治的急性ST段抬高心肌梗死患者90例随机等分为对照组和观察组,对照组采取常规急救护理,观察组采取分级分区护理。比较两组患者急救时间、并发症发生率。结果 观察组患者急救时间短于对照组(P <0. 05),并发症发生率低于对照组(P <0. 05)。结论 分级分区护理在急性ST段抬高心肌梗死患者急救中的应用效果较好,受到患者认可,值得临床推广应用。

体现汉语韵律特征的分联小段

本文从韵律句法学的角度分析汉语小段大量存在这一语法现象,通过对比汉语和英语的音步结构,说明汉语小段得以生成的原因和条件。文章指出,汉语音步的结构特点为间断与韵律、语法成分边界的契合提供了可能性,而这种契合便是小段的基本成因。与汉语不同,英语音步构成过程中,轻音节的前向自然脱离导致韵律成分与语法成分的大量错位,使间断不易发生。同时,文章阐述小段与正段之间的分联形式,并分析小段作为不同种类的附加语和作为过程参与者成分的不同功能。