异种材料相接触热传导的变分原理和有限元计算

本文应用限制变分的思想,就两种不同材料相接触处的热传导问题,构造了一个新的温度泛函,并且证明了这个泛函的变分等价于相应的微分方程和边界条件,从而使应用有限元方法求解具有交界面的热传导问题更为科学和合理。     

民用卫星电视天线的直径计算与跟踪

介绍了从一个已知的民用或国际通信卫星成功地接收到电视图像时,所需天线口径的计算式和利用抛物面天线如何跟踪太空中卫星的知识。     

天线罩覆盖的波束近轴场

本文根据复射线法对通过介质天线罩的高斯波束场进行近轴近似分析。实空间的轴向复射线追综大大简化了计算过程,而复相位差、反射-传输系数和曲面扩散系数的进一步校正则提供了相当精确的结果。所得数字结果表明,在波束的近轴区域内为获得同样的计算精度,近轴近似法所需要的计算机时间远小于复射线追综法的时间。     

介连兼类词“和”“与”“同”“跟”的共性比较

现代汉语中,词性被定为介连兼类词的"和""与""同""跟"这四个词有很多相似之处。总结了这四个词在词类和语义上的共性,并探讨了它们的不同之处,进一步得出在一定语境中,这四个词既可以做介词,也同时可以做连词。因此,为了表达需要,在使用这些词时一定要明确他们的适用语境。     

On the use of different metrics for assessing complex pattern reproductions

Nowadays, there is an increasing interest in multi-point models and their applications in Earth sciences. However, users not only ask for multi-point methods able to capture the uncertainties of complex structures and to reproduce the properties of a training image, but also they need quantitative tools for assessing whether a set of realizations have the properties required. Moreover, it is crucial to study the sensitivity of the realizations to the size of the data template and to analyze how fast realization-based statistics converge on average toward training-based statistics. In this paper, some similarity measures and convergence indexes, based on some physically measurable quantities and cumulants of high-order, are presented. In the case study, multi-point simulations of the spatial distribution of coarse-grained limestone and calcareous rock, generated by using three templates of different sizes, are compared and convergence toward training-based statistics is analyzed by taking into account increasing numbers of realizations.     

形似与神似，求真与求美--从本体诗歌翻译理论的角度分析

本体诗歌翻译理论主要探讨译文与原文在形式与内容上的关系。译文与原文应该达到形似还是神似，译者应该求真还是求美，这是翻译界一直争论的话题。按照“形似与神似，求真与求美”的关系来分析江枫先生对艾米莉·狄金森的两首诗歌“暴风雨夜”和“篱笆那边”的翻译，可以看出，标点符号、遣词、诗歌的韵式和诗人的创作风格等方面体现了江枫译文的特点和风格：译文选词简单但富有张力，行文简约而内敛，与原诗风格颇似；但由于过于追求简约而稍显生硬和晦涩。总之，江枫的译文是形似与神似结合的典范，体现其“形似而后神似”的主张以及“简约而忠实”的风格，但并未完全实现“求真与求美”的完美结合。     

Bayesian sample‐size determination methods considering both worthwhileness and unpromisingness for exploratory two‐arm randomized clinical trials with binary endpoints

A randomized exploratory clinical trial comparing an experimental treatment with a control treatment on a binary endpoint is often conducted to make a go or no‐go decision. Such an exploratory trial needs to have an adequate sample size such that it will provide convincing evidence that the experimental treatment is either worthwhile or unpromising relative to the control treatment. In this paper, we propose three new sample‐size determination methods for an exploratory trial, which utilize the posterior probabilities calculated from predefined efficacy and inefficacy criteria leading to a declaration of the worthwhileness or unpromisingness of the experimental treatment. Simulation studies, including numerical investigation, showed that all three methods could declare the experimental treatment as worthwhile or unpromising with a high probability when the true response probability of the experimental treatment group is higher or lower, respectively, than that of the control treatment group.     

Indicator development as a site of collective imagination? The case of European Commission policies on the circular economy

ABSTRACT

In recent years the concept of the circular economy gained prominence in EU policy-making. The circular economy promotes a future in which linear ‘make-use-dispose’ cultures are replaced by more circular models. In this paper, we use the concept of sociotechnical imaginaries to ask how an imaginary of circularity has been assembled and stabilized, which imaginative resources were drawn on, and how goals, priorities, benefits and risks haven been merged with discourses of innovation, sustainability and growth. Drawing on policy documents and interviews with policy officers of the European Commission, we argue that the monitoring framework and indicator development function as a site collective imagination in which desirable ‘circular’ futures are co-produced. These futures are imagined to provide novel opportunities for the private sector and to generate jobs and economic growth while at the same time improving the natural environment as measured by selected environmental indicators.     

问答社区知识传播者网络声望、行动相似度与知识传播效果

基于社会交换理论和趋同理论等,构建问答社区知识传播者关注关系网络声望、传播者行动相似度和知识传播效果三者之间的相互作用关系,并通过含滞后项的联立方程组模型对上述关系进行实证分析,挖掘问答社区内知识传播的影响机制。研究表明:知识传播者关注关系网络声望和知识传播效果之间存在着相互促进作用;知识传播者的行动相似度对传播者关注关系网络声望有正向影响;知识传播环境特征和知识内容丰富度对知识的传播效果有正向影响;在特定话题下,知识内容丰富度在知识传播者关注关系网络声望对知识传播效果影响中起负向调节作用。