共查询到19条相似文献,搜索用时 62 毫秒
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低温容器是气体液化分离加工工业中的重要设备,绝热设计是低温容器设计的重要组成部分,它直接影响低温容器的日蒸发率。在不同的绝热材料和一定漏热温差的条件下,给出了普通绝热和真空粉末绝热型低温容器的日蒸发率与热材料的有效导热系数以及绝热层厚度之间的关系曲线。为简化设计和比较低温容器的特性提供方法和依据。 相似文献
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低温容器蒸发率试验及蒸发量波动分析 总被引:2,自引:2,他引:0
用液氮为试验工质,对3个具有相同结构的35m3高真空多层绝热容器在不同地点进行了日蒸发率试验,对试验中得到的蒸发量与环境温度和环境压强的变化关系进行了分析,认为环境温度的波动虽然是容器内蒸发量波动的内因,但表观蒸发量的波动受大气压变化的影响更大,呈即时的相反关系。同时认为,为了能更真实地反映容器内的实际蒸发率值,应结合气压曲线,对有效测试时段内的总流量取平均值来计算蒸发率,以消除环境波动的影响。 相似文献
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建立了用于计算低温容器蒸发流量的数学模型,得出了蒸发流量与环境温度、环境压力之间的关系。结果显示,瞬时蒸发流量变化不但受到环境压力影响,同时还受到环境压力变化率以及容器内液体量的影响。提出了衡量环境压力变化对蒸发流量影响程度的无因次量,讨论了在不同漏热、不同装载量情况下环境压力变化的影响程度。以液氮为工质,对35立方米高真空多层绝热低温容器在不同地点进行了试验,试验结果与计算结果符合较好。 相似文献
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《中国新技术新产品》2015,(14)
本文简要阐述了当前电力市场负荷预测的手段,并通过引入多元线回归分析的主要理论,研究电网企业在用电量与宏观经济其他相关因素方面存在的内有关系,揭示其运行规律。 相似文献
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In a recent paper González Manteiga and Vilar Fernández (1995) considered the problem of testing linearity of a regression
underMA(∞) structure of the errors using a weightedL
2-distance between a parametric and a nonparametric fit. They established asymptotic normality of the corresponding test statistic
under the hypothesis and under local alternatives. In the present paper we extend these results and establish asymptotic normality
of the statistic under fixed alternatives. This result is then used to prove that the optimal (with respect to uniform maximization
of power) weight function in the test of González Manteiga and Vilar Fernández (1995) is given by the Lebesgue measure independently
of the design density.
The paper also discusses several extensions of tests proposed by Azzalini and Bowman (1993), Zheng (1996) and Dette (1999)
to the case of non-independent errors and compares these methods with the method of Gonzálcz Manteiga and Vilar Fernández
(1995). It is demonstrated that among the kernel based methods the approach of the latter authors is the most efficient from
an asymptotic point of view. 相似文献
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对低温容器分别在环境温度下和有外热源条件下进行热响应实验,发现低温容器静态蒸发率呈周期性变化,但变化周期仅为环境温度变化周期的1/2,环境温度的周期性变化并非是使高真空多层绝热容器蒸发率测量时产生周期变化的主要因素。在进行外热源加热容器外壁实验时发现,外壁温度变化并没有对低温容器的漏热量产生明显的影响,低温容器的绝热层对低温容器外壁面的温度波动有较强的衰减及延迟作用,热量在传入的过程中发生了剧烈的衰减,使容器内壁近似形成一个"等温层",从而使高真空多层绝热低温容器的漏热量几乎不受外界环境温度变化的影响。 相似文献
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介绍真空粉末绝热低温液体贮槽需要的工作真空度,通过实例计算得出:提高封结真空度对增加贮槽的真空寿命的程度有限,漏率才是影响真空寿命的关键因素。比较国内外对封结真空度的要求后,阐明降低封结真空度指标的可行性和重要意义。 相似文献
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Keisuke Teramoto Kei Hirose 《International journal for numerical methods in engineering》2022,123(2):530-546
In the field of materials science and engineering, statistical analysis and machine learning techniques have recently been used to predict multiple material properties from an experimental design. These material properties correspond to response variables in the multivariate regression model. In this study, we conduct a penalized maximum likelihood procedure to estimate model parameters, including the regression coefficients and covariance matrix of response variables. In particular, we employ -regularization to achieve a sparse estimation of The regression coefficients and inverse covariance matrix of response variables. In some cases, there may be a relatively large number of missing values in the response variables, owing to the difficulty of collecting data on material properties. We therefore propose a method that incorporates a correlation structure among the response variables into a statistical model to improve the prediction accuracy under the situation with missing values. The expectation maximization algorithm is also constructed, which enables application to a dataset with missing values in the responses. We apply our proposed procedure to real data consisting of 22 material properties. 相似文献
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针对林德公司对大型低温液体贮罐日蒸发率的高要求,联合国内制造商进行技术攻关,选择质量符合要求的保温材料,根据国产保温材料的参数修改贮罐的设计参数。按照国内相关规范对2000m3液氧贮罐进行日蒸发率实际测试,其结果达到林德公司的标准。 相似文献