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混凝土屋面工程防水研究(七):工程防水耐久性评定方法与建议
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作者 徐洪涛 肖绪文 +5 位作者 王茜 朱志远 霍倩男 朱彤 张勇 周辉 《施工技术(中英文)》 2024年第23期75-82,共8页
屋面工程防水耐久性是一定时间内受影响因素作用屋面维持允许渗漏量的能力,由于影响因素与衰减机理的复杂性,防水耐久性需结合经验和量化方法判定。通过“半经验、半概率”因子计算方法对SBS改性沥青防水卷材屋面的耐久性进行预测、分析... 屋面工程防水耐久性是一定时间内受影响因素作用屋面维持允许渗漏量的能力,由于影响因素与衰减机理的复杂性,防水耐久性需结合经验和量化方法判定。通过“半经验、半概率”因子计算方法对SBS改性沥青防水卷材屋面的耐久性进行预测、分析,参照工作年限是耐久性判定的基准,也是最关键的部分。因子取值需谨慎,尽量减少修正因子类别。由于不确定因素的存在,耐久性适合采用分布特征、置信区间进行表达。 展开更多
关键词 混凝土 屋面 防水 耐久性 工作年限 因子计算法
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基于人工材料密度的新型拓扑优化理论和算法研究 被引量:64
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作者 左孔天 陈立平 +2 位作者 钟毅芳 王书亭 张云清 《机械工程学报》 EI CAS CSCD 北大核心 2004年第12期31-37,共7页
对基于人工材料密度的拓扑优化理论作了深入分析;推导出了一种基于人工材料密度的拓扑优化准则算法,将该算法应用于拓扑优化的计算中,并给出了基于人工材料密度的拓扑优化迭代分析流程;提出了一种卷积因子方法,用于消除拓扑优化计算结... 对基于人工材料密度的拓扑优化理论作了深入分析;推导出了一种基于人工材料密度的拓扑优化准则算法,将该算法应用于拓扑优化的计算中,并给出了基于人工材料密度的拓扑优化迭代分析流程;提出了一种卷积因子方法,用于消除拓扑优化计算结果中易出现的棋盘格式和多孔材料现象;通过数值计算验证了理论和算法的有效性;分析讨论了不同优化参数对拓扑优化计算结果的影响。 展开更多
关键词 人工材料密度 拓扑优化优化准则卷积因子数值计算
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大型客船厨房空调通风系统设计计算
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作者 杨勇 张新桥 +1 位作者 胡思平 孙小亮 《船舶工程》 CSCD 北大核心 2021年第S01期263-266,共4页
一般商船的厨房空调通风系统设计都是按确定空调送风温度、以及排出厨房辐射散热和换气次数的风量计算来考虑的,并没有涉及怎么有效地排除厨房烹饪设备在烹饪过程中产生的油烟、异味以及水蒸气,厨房通风效果往往达不到预期效果。大型客... 一般商船的厨房空调通风系统设计都是按确定空调送风温度、以及排出厨房辐射散热和换气次数的风量计算来考虑的,并没有涉及怎么有效地排除厨房烹饪设备在烹饪过程中产生的油烟、异味以及水蒸气,厨房通风效果往往达不到预期效果。大型客船厨房由于厨房种类数量繁多,且单个厨房面积较大、所需集气罩数量和类型也比一般商船的厨房要多,厨房空调风量的确定不能简单的按照换气次数和设备辐射散热量来算,还应充分考虑烹饪设备对集气罩排风量的要求。文章介绍了厨房集气罩排风量的计算方法,通过研究集气罩下面的不同烹饪设备的加热热源、烹饪设备加热功率及不同烹饪设备类型的散热特性,对于每个烹饪设备在烹饪过程中产生的油烟和异味、蒸煮过程中散发的水蒸气等,都需要有针对性的进行处理,分别计算不同烹饪设备工作过程种所需的集气罩排风量,保障厨房的环境。 展开更多
关键词 船用厨房集气罩 辐射热负荷 上升羽流热负荷 排气因子计算法 基于热负荷的排风量计算
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Calculations of stability of alloyed cementite from valance electron structure
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作者 王红军 刘宏玉 +4 位作者 刘礼 曾晓宇 卢建夺 林冲 徐红兵 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第2期259-269,共11页
Based on the empirical electronic theory of solids and molecules (EET), the actual model for unit cell of cementite (0-FeaC) was built and the valence electron structures (VES) of cementite with specified site a... Based on the empirical electronic theory of solids and molecules (EET), the actual model for unit cell of cementite (0-FeaC) was built and the valence electron structures (VES) of cementite with specified site and a number of Fe atoms substituted by alloying atoms of M ( M=Cr, V, W, Mo, Mn ) were computed by statistical method. By defining P as the stability factor, the stability of alloyed cementite with different numbers and sites of Fe atoms substituted by M was calculated. Calculation results show that the density of lattice electrons, the symmetry of distribution of covalent electron pairs and bond energy have huge influence on the stability of alloyed cementite. It is more stable as M substitutes for FeE than for Fe1. The alloyed cementite is the most stable when Cr, Mo, W and V substitute for 2 atoms of Fe2 at the sites of Nos. 2 and 3 (or No. 6 and No. 7). The stability of alloyed cementite decreases gradually as being substitutional doped by W, Cr, V, Mo and Mn. 展开更多
关键词 valence electron structure alloyed cementite stability density of lattice electrons symmetry of bonds bond energy
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Calculation of impact factor of vibrator oscillation in offset printing based on fuzzy controller and genetic algorithm
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作者 初红艳 Yang Junjing Cai Ligang 《High Technology Letters》 EI CAS 2015年第1期15-21,共7页
In the inking system of an offset printing press,a vibrator roller distributes ink not only in the circumferential direction but also in the axial direction.In the control process,if ink amount is determined only by t... In the inking system of an offset printing press,a vibrator roller distributes ink not only in the circumferential direction but also in the axial direction.In the control process,if ink amount is determined only by the dot area coverage without considering the impact of vibrator roller's oscillation,the printing colour quality will be reduced.This paper describes a method of calculating the impact factor of vibrator roller' s oscillation.First,the oscillation performance is analyzed and sample data of impact factor is got.Then,a fuzzy controller used for the calculation of the impact factor is designed,and genetic algorithm is used to optimize membership functions and obtain the fuzzy control rules automatically.This fuzzy controller can be used to calculate impact factors for any printing condition,and the impact factors can be used for ink amount control in printing process and it is important for higher printing colour quality and lowering ink and paper waste. 展开更多
关键词 offset printing colour quality control impact factor fuzzy control genetic algorithm
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The geometric factor of high energy protons detector on FY-3 satellite 被引量:7
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作者 ZHANG ShenYi ZHANG XianGuo +10 位作者 WANG ChuiQin SHEN GuoHong JIN Tao ZHANG BinQuan SUN YueQiang ZHU GuangWu LIANG JinBao ZHANG XiaoXin LI JiaWei HUANG Cong HAN Ying 《Science China Earth Sciences》 SCIE EI CAS 2014年第10期2558-2566,共9页
Geometric factor is the key parameter for inversion of particle spectrum in space particle detection. Traditional geometric factor is obtained through the method of numerical calculation with the actual structure of t... Geometric factor is the key parameter for inversion of particle spectrum in space particle detection. Traditional geometric factor is obtained through the method of numerical calculation with the actual structure of the detector as the input condition. The degree of accuracy for data inversion is reduced since traditional geometric factor fails to take into account the physical process of interaction between the particle and substance as well as the influence of factors such as the particle interference between different energy channels on the measurement result. Here we propose an improved geometrical factor calculation method, the concept of which is to conduct actual structural modelling of the detector in the GEANT4 program, consider the process of interaction between the particle and substance, obtain the response function of the detector to particles of different energy channels through the method of Monte Carlo simulation, calculate the influence of contaminated particle on the geometrical factor, and finally get the geometrical factors for different energy channels of the detector. The imrpoved geometrical factor obtained through the method has carried out inversion for the data of high energy protons detector on China's FY-3 satellite, the energy spectrum after which is more in line with the power law distribution recognized by space physics. The comparison with the measured result of POES satellite indicates that the FY-3 satellite data are in good accordance with the satellite data, which shows the method may effectively improve the quality of data inversion. 展开更多
关键词 geometrical factor response function particle radiation space detection FY-3
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