电控PPVI柴油机喷射系统参数匹配

本文介绍了新型电控直列泵—管—阀—嘴（ＰＰＶＩ） 柴油机的喷射系统参数对燃烧过程的影响。对不同的启喷压力、不同的电磁阀位置、不同的油管长度、不同的喷油器及不同的柱塞直径,在１２００ ～２８００ｒ／ｍｉｎ 范围内,及脉宽１０ ℃Ａ条件下,进行了匹配试验,经过分析,得到了这种燃油喷射系统的较佳参数组合     

FIA型微生物探针动态响应过程的研究Ⅰ──谷氨酸的测定

将固定化细胞柱和简单的流动注射系统相结合，以大肠杆菌（Ｅ．Ｃｏｌｉ）为工作菌株配合ＣＯ＿２选择性电极，制成谷氨酸微生物传感器。它具有以下特性：传感器对谷氨酸溶液的适用测量浓度范围为４００～２０００ｍｇ／Ｌ谷氨酸；一个样品的检测在２０ｍｉｎ内完成；固定化细胞柱的使用寿命在４周以上；除Ｌ－精氨酸和Ｌ－谷氨酰胺外，其余氨基酸均不干扰传感器对谷氨酸的测定。     

单层氮化硼空位缺陷的形成与稳定性的研究

本文利用密度泛函理论方法研究了单层氮化硼中多原子空位缺陷的结构和稳定性。研究发现缺陷多为对称结构,并且存在幻数现象。通过对不同尺寸缺陷离解能的回归分析,发现对于尺寸较大的缺陷,周围的氮原子数越多,缺陷越稳定,该结论很好的解释了实验中观察到的现象。     

A methodological approach to analyze vulnerability of interdependent infrastructures

The infrastructures are interconnected and interdependent on multiple levels, the failure of one infrastructure can result in the disruption of other infrastructures, which can cause severe economic disruption and loss of life or failure of services. A methodological approach to analyze vulnerability of interdependent infrastructures has been introduced in this paper, two types of vulnerability are studied: structural vulnerability and functional vulnerability. Infrastructure topologies are only used for analysis on structural vulnerability while operating regimes of different infrastructures are further considered to analyze functional vulnerability. For these two types of vulnerability, interdependent effects are mainly studied and the effects of interdependence strength between infrastructures have also been analyzed. The analysis on structural vulnerability will be helpful to design or improve the infrastructures in the long run while the discussion on functional vulnerability will be useful to protect them in the short term. The methodology introduced in this paper will be advantageous to comprehensively analyze the vulnerability of interdependent infrastructures and protect them more efficiently.     

Self-Supervised Task Augmentation for Few-Shot Intent Detection

Few-shot intent detection is a practical challenge task, because new intents are frequently emerging and collecting large-scale data for them could be costly. Meta-learning, a promising technique for leveraging data from previous tasks to enable efficient learning of new tasks, has been a popular way to tackle this problem. However, the existing meta-learning models have been evidenced to be overfitting when the meta-training tasks are insufficient. To overcome this challenge, we present a novel self-supervised task augmentation with meta-learning framework, namely STAM. Firstly, we introduce the task augmentation, which explores two different strategies and combines them to extend meta-training tasks. Secondly, we devise two auxiliary losses for integrating self-supervised learning into meta-learning to learn more generalizable and transferable features. Experimental results show that STAM can achieve consistent and considerable performance improvement to existing state-of-the-art methods on four datasets.     

主元分析在变压器故障检测与识别中的应用

针对IEC三比值法进行变压器故障诊断存在缺编码、编码边界模糊和诊断率偏低的问题,提出了采用主元分析和重构贡献图的故障诊断方法。在建立的PCA(Principal Component Analysis)统计过程模型上,构建SPE、T2统计量和重构贡献指标对变压器故障进行检测,并分析了贡献图法和重构贡献法的故障诊断性能。仿真结果表明基于主元分析和重构贡献图的故障诊断方法对数据更敏感,能够有效弥补IEC三比值法的不足,提高故障诊断正确率。     

大冶灵宝铁矿采场稳定性综合分析评价

采用RMR及Q系统岩体分类方法对灵宝铁矿采场整体稳定性进行分析,并运用ANSYS软件综合评价采场细部稳定性数值分析的结果及该矿采场的稳定性。分析得出该矿在当前条件下采场稳定性良好,为安全回采矿区残留矿体提供了理论依据。     

Pullulan acetate coated magnetite nanoparticles for hyper-thermia: Preparation, characterization and in vitro experiments

Amphipathic polymer pullulan acetate (PA)-coated magnetic nanoparticles were prepared and characterized by various physicochemical means. The cytotoxicity and cellular uptake of the magnetic nanoparticles were examined. The hyperthermic effect of the magnetic nanoparticles on tumor cells was evaluated. Transmission electron microscopy (TEM) showed that the PA coated magnetic nanoparticles (PAMNs) had spherical morphology. Dynamic light scattering (DLS) showed that the size distribution of PAMNs was unimodal,with an average diameter of 25.8 nm ± 6.1 nm. The presence of the adsorbed layer of PA on the magnetite surface was confirmed by Fourier transform infrared (FTIR) spectroscopy. Magnetic measurements revealed that the saturation magnetization of the PAMNs reached 51.9 emu/g and the nanoparticles were superparamagnetic. Thermogravimetric analysis (TGA) showed that the Fe₃O₄ particles constituted 75 wt% of the PAMNs. The PAMNs had good heating properties in an alternating magnetic field. Cytotoxicity assay showed that PAMNs exhibited no significant cytotoxicity against L929 cells. TEM results showed that a large number of PAMNs were internalized into KB cells. PAMNs have good hyperthermia effect on KB cells in vitro by magnetic field induced hyperthermia. These novel magnetic nanoparticles have great potential as magnetic hyperthermia mediators.      

Comparison of policies on vehicle ownership and use between Beijing and Shanghai and their impacts on fuel consumption by passenger vehicles

The fast growth of vehicle population in China has caused problems such as traffic congestion and excessive fuel consumption. There have been demands for policy control on growth in private vehicle travel demand. Beijing and Shanghai are China’s first two cities to implement policies on vehicle ownership and use. In this paper, we compared policies in the two cities and estimated their impacts on fuel consumption by passenger vehicles. The limitation of vehicle use in Beijing provides limited but immediate reduction in fuel consumption. The limitation of vehicle ownership in Shanghai provides large potential of fuel conservation in a longer term. Under current policy, fuel consumptions by passenger vehicles in Beijing and Shanghai in 2020 were estimated to reach 7.5 and 3.9 billion liters, respectively. The experiences of Beijing and Shanghai are highly relevant for cities in China and abroad that are facing the same problems.     

基于有效数据的经验模态分解快速算法研究

在介绍了经验模态分解（简称EMD）方法的理论和算法基础上，为了提高EMD算法的速度，提出了基于有效数据的EMD快速算法，即通过EMD分解中止的计算区域限定于有效数据段来实现算法的提速。通过对非线性信号的实验研究表明，基于有效数据的EMD快速算法不但能显著提高算法的速度，而且还可以提高算法的精度。该研究成果能广泛地用于信号时频分析领域。