PuO2含量对MOX燃料组件物理特性的影响

当超临界水冷堆组件采用铀与钚的氧化物混合而成的MOX燃料时,与普通UO_2燃料相比其中子学特性存在差异。为了研究PuO_2含量对组件物理特性的影响,采用蒙特卡罗方法计算得到了不同PuO_2含量时MOX燃料物理特性参数,包括俘获裂变比、总微观裂变截面、燃料每次裂变平均释放的能量、每次裂变释放的中子数及有效裂变中子数。进一步得到了装载不同含量PuO_2时MOX燃料组件特性参数,包括能谱、Keff、相对功率、相对功率峰值和缓发中子份额。研究结果对MOX燃料组件的设计有一定参考价值。     

用MCM验证测长仪示值误差的测量不确定度GUM法评定

本文用蒙特卡洛法对测长仪示值误差的测量不确定度的GUM法评定进行了验证,结果一致,验证通过。     

Residual Feature Attentional Fusion Network for Lightweight Chest CT Image Super-Resolution

The diagnosis of COVID-19 requires chest computed tomography (CT). High-resolution CT images can provide more diagnostic information to help doctors better diagnose the disease, so it is of clinical importance to study super-resolution (SR) algorithms applied to CT images to improve the resolution of CT images. However, most of the existing SR algorithms are studied based on natural images, which are not suitable for medical images; and most of these algorithms improve the reconstruction quality by increasing the network depth, which is not suitable for machines with limited resources. To alleviate these issues, we propose a residual feature attentional fusion network for lightweight chest CT image super-resolution (RFAFN). Specifically, we design a contextual feature extraction block (CFEB) that can extract CT image features more efficiently and accurately than ordinary residual blocks. In addition, we propose a feature-weighted cascading strategy (FWCS) based on attentional feature fusion blocks (AFFB) to utilize the high-frequency detail information extracted by CFEB as much as possible via selectively fusing adjacent level feature information. Finally, we suggest a global hierarchical feature fusion strategy (GHFFS), which can utilize the hierarchical features more effectively than dense concatenation by progressively aggregating the feature information at various levels. Numerous experiments show that our method performs better than most of the state-of-the-art (SOTA) methods on the COVID-19 chest CT dataset. In detail, the peak signal-to-noise ratio (PSNR) is 0.11 dB and 0.47 dB higher on CTtest1 and CTtest2 at SR compared to the suboptimal method, but the number of parameters and multi-adds are reduced by 22K and 0.43G, respectively. Our method can better recover chest CT image quality with fewer computational resources and effectively assist in COVID-19.     

Non-fragile dynamic output feedback H∞ control for discrete-time systems with FWL consideration

The non-fragile dynamic output feedback H _∞ controller design problem is investigated. The controller to be designed is assumed to be with additive gain variations. A two-step procedure is proposed to develop sufficient conditions for the non-fragile H _∞ controller design by employing the structured vertex separator. A comparison between the proposed and the existing controller design methods is provided, and a numerical example is carried out to support the theoretical findings.     

基于LabVIEW的吸声系数测试系统设计

介绍了基于图形化语言LabVIEW开发环境,采用双传声器法测量各种材料吸声系数的方法;利用频谱细化技术对算法进行了优化,实现了对吸声系数快速、连续、稳定的测量,并可以方便地保存项目参数及对测试结果进行分析、拼接、保存、复现及报表;在相同的实验条件下,采用多种实验材料与B&K PULSE系统进行对比测试,并对海绵的测试结果进行了具体分析;结果表明,采用本系统所测得曲线与PULSE测试结果吻合度很高,证明该系统测试精确度高,性能稳定可靠,操作简单,达到了设计要求,有助于各种吸声材料的研发。     

基于词性的文本挖掘算法在IDS日志中的应用

提出一种以词性为参考值的文本挖掘算法,能有效挖掘与种子词有关的关联规则。基于Bootstrapping算法思想,既减少了预处理阶段对于词根还原的依赖,能处理日志中出现的中文词汇。增加了对于日志文本上下的理解,提高了关联规则的有效性,并应用与IDS日志挖掘之中,有效改善挖掘效率,为规则库提供关联规则。     

Nonlinear ceramics for tunable microwave devices

The research on materials and systems for tunable microwave devices has gained attraction within the last years. The radio frequency characterization and the component design of tunable microwave components based on dielectric ceramics especially barium-strontium-titanate (BST) are presented in this second part, whereas the basic material properties are discussed in detail in the first part. After a short introduction to the processing technology used for the fabrication of tunable components based on a BST thick film, the relations between microwave properties and material properties as well as the microstructure are presented in detail. The design process for tunable microwave components based on BST thick films is described. Especially the considerations related to micro- and macrostructure and their connection are highlighted. The paper closes with two different application examples: a reconfigurable array antenna for satellite communication and varactors for high power applications.