基于模糊评判的数控机床零部件制造工艺FMECA研究

以数控机床零部件的制造工艺为研究对象,对其实施改进的制造工艺FMECA,通过梯形模糊数评判的方法确定出工艺FMECA中风险优先数的排序,利用模糊综合评判方法确定出工艺系统的风险等级,有效地找出薄弱工艺环节并采取改进措施,从而提高数控机床零部件制造工艺可靠性.     

欧盟"气候行动与可再生能源综合计划"建议草案:核心要点与战略意义

概述了欧盟"气候行动与可再生能源综合计划"建议草案的出台背景、核心要点和主要内容,评价了各方反应及该建议草案的优点和缺点,分析了该建议草案与<京都议定书>第二承诺期气候谈判的联系及其对碳市场的影响.最后,针对中国参与清洁发展机制(CDM)活动,提出了个人的思考和建泌.     

Acidity of Aerosols during Winter Heavy Haze Events in Beijing and Gucheng,China

We investigated the acidity and concentrations of water-soluble ions in PM_2.5 aerosol samples collected from an urban site in Beijing and a rural site in Gucheng, Hebei Province from November 2016 to January 2017 to gain an insight into the formation of secondary inorganic species. The average SO₄^2–, NO₃^–, and NH₄⁺ concentrations were 8.3, 12.5, and 14.1 μg m^–3, respectively, at the urban site and 14.0, 14.2, and 24.2 μg m^–3, respectively, at the rural site. The nitrogen and sulfur oxidation ratios in urban Beijing were correlated with relative humidity (with correlation coefficient r = 0.79 and 0.67, respectively) and the aerosol loadings. Based on a parameterization model, we found that the rate constant of the heterogeneous reactions for SO₂ on polluted days was about 10 times higher than that on clear days, suggesting that the heterogeneous reactions in the aerosol water played an essential role in haze events. The ISORROPIA II model was used to predict the aerosol pH, which had a mean (range) of 5.0 (4.9–5.2) and 5.3 (4.6–6.3) at the urban and rural site, respectively. Under the conditions with this predicted pH value, oxidation by dissolved NO₂ and the hydrolysis of N₂O₅ may be the major heterogeneous reactions forming SO₄^2– and NO₃^– in haze. We also analyzed the sensitivity of the aerosol pH to changes in the concentrations of SO₄^2–, NO₃^–, and NH₄⁺ under haze conditions. The aerosol pH was more sensitive to the SO₄^2– and NH₄⁺ concentrations with opposing trends, than to the NO₃^– concentrations. The sensitivity of the pH was relatively weak overall, which was attributed to the buffering effect of NH₃ partitioning.     

海温作用与低频振荡

提出一个求定常方程平衡数值解的方法,并利用这个方法求得了雷州半岛海风环流的稳定数值解,在一定下边界强迫下得到了和观侧相一致的环流状态,进而讨论了大气参数对海风环流的影响,试验表明,所提出的求解方法是有效的.     

遗传算法在组分温度反演中的应用

介绍了遗传算法的主要内容和工作原理。在连续植被热辐射方向性模型的基础上,从热红外多角度遥感数据中,同时反演混合像元组分温度、土壤比辐射率以及叶面积指数。大量试验表明,利用遗传算法反演组分温度效果非常好。在宽松的先验知识条件下,该方法可以解决不确定性反演问题     

地面沉降时空形变场的构建方法研究

由于离散分布的精密水准测量数据只能对点状沉降信息进行监测分析,描述特定时间点的静态空间趋势,无法表达区域性地面沉降整体时空变化.该文提出一种地面沉降时空形变场的构建方法,在多项式拟合法构建形变场的基础上考虑时间项,通过探索地面沉降量与坐标、时间的关系,对区域地面形变的整体效果进行拟合,构建地面沉降时空形变场.该方法顾及...     

基于地理探测器的合肥市热岛效应影响因素分析

地表温度是城市热岛效应的重要指标。本文利用合肥市2018年4月10日的Landsat-8 OLI影像数据,经过预处理后,采用大气校正法反演地表辐射温度,并提取研究区域的归一化差分植被指数(NDVI)、归一化差分水体指数(NDWI)。通过地理探测器模型,探测地表温度和海拔、NDVI、NDWI等因子之间的影响关系。结果表明：合肥市存在热岛效应。通过分析地理探测器模型的探测结果可知：从单一因子探测角度分析,影响合肥市地表温度的主导因子为NDVI和NDWI;从两因子交互作用影响角度分析,NDVI对因子交互作用的影响最强。研究结果有利于分析合肥市热岛效应的影响因素,为城市规划、生态环境保护提供科学依据。     

Signal acquisition of Luojia-1A low earth orbit navigation augmentation system with software defined receiver

Low Earth Orbit (LEO) satellite navigation signal can be used as an opportunity signal in the case of a Global Navigation Satellite System (GNSS) outage, or as ...     

联合战役地形分析

首次提出联合战役地形分析的概念,并分析了联合战役地形分析应用的主要时机和要求。论述确定地形分析基本任务的逻辑关系,并分别研究了联合战役地形分析各基本内容的概念与分析方法。