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关键词： Multi-terminal DC (MTDC) network   VSC control   sub-synchronous oscillations (SSOs)   sub-synchronous interactions (SSIs)  

摘要： This paper proposes a method of open-loop modal analysis to examine the subsynchronous interactions (SSIs) introduced by the converter control in an ac power system integrated with a multiterminal dc network. A control loop of the voltage source converters (VSCs) is selected to derive a closed-loop interconnected model, wherein the selected control loop and the rest of the power system are modeled as two interconnected open-loop subsystems. The analysis in this paper indicates that under the condition of open-loop modal proximity, strong SSIs may be introduced by the selected VSC control loop. It is very likely that the strong SSIs may degrade the damping of power system sub synchronous oscillations (SSOs). It is proposed that the damping degradation be estimated by calculating the open-loop SSO residues. Hence, the modal analysis for the open-loop subsystems can identify the open-loop modal proximity and estimate the degree of stability degradation under the condition of open-loop modal proximity. In addition, the VSC control loops and the synchronous generators contributing to the stability degradation can be identified. The application of the proposed method of open-loop modal analysis is demonstrated through example power systems in this paper.

关键词： Pararhizobium haloflavum   Soil samples   Sewage treatment tank   Taxonomy  

摘要： A Gram-stain negative, aerobic, motile and ovoid- to rod-shaped bacteria strain, designated XC0140(T), was isolated from soil samples near the sewage treatment tank of a chemical factory in Zhejiang Province, China, and subjected to polyphasic taxonomic investigation. Strain XC0140(T) grew at 10-37 A degrees C and pH 6.0-9.0 (optimum, 35 A degrees C and pH 7.5) and with 0-17% (w/v) NaCl (optimum, 1%). According to phylogenetic analysis based on 16S rRNA gene sequences, strain XC0140(T) was assigned to the genus Pararhizobium with high 16S rRNA gene sequence similarity of 95.97% to "Pararhizobium helanshanense CCNWQTX14(T"), followed by Pararhizobium sphaerophysae CCNWGS0238(T) (95.95%). Chemotaxonomic analysis showed that strain XC0140(T) contains ubiquinone-10 as the predominant respiratory quinone and possessed summed feature 8 (comprising C-18: 1 omega 7c and/or omega 6c), 11-methyl C-18:1 omega 7c, C-18: 0 and C-16: 0 as predominant forms of fatty acids. The polar lipids of strain XC0140(T) consisted of seven phospholipids (PL), two aminolipids (AL), one glycolipid (GL) and three unidentified lipids (L1, L2 and L3). The DNA G+C content was 62.7 mol%. Based on the polyphasic taxonomic characterization, strain XC0140(T) is considered to represent a novel species of the genus Pararhizobium, for which the name Pararhizobium haloflavum sp. nov. is proposed. (type strain XC0140(T) = MCCC 1K03228(T) = KCTC 52582(T)).

关键词： hyperspectral image classification   deep learning   residual networks   co-training   sample selection  

摘要： This paper studies the classification problem of hyperspectral image (HSI). Inspired by the great success of deep neural networks in Artificial Intelligence (Al), researchers have proposed different deep learning based algorithms to improve the performance of hyperspectral classification. However, deep learning based algorithms always require a large-scale annotated dataset to provide sufficient training. To address this problem, we propose a semi-supervised deep learning framework based on the residual networks (ResNets), which use very limited labeled data supplemented by abundant unlabeled data. The core of our framework is a novel dual-strategy sample selection co-training algorithm, which can successfully guide ResNets to learn from the unlabeled data by making full use of the complementary cues of the spectral and spatial features in HSI classification. Experiments on the benchmark HSI dataset and real HSI dataset demonstrate that, with a small number of training data, our approach achieves competitive performance with maximum improvement of 41% (compare with traditional convolutional neural network (CNN) with 5 initial training samples per class on Indian Pines dataset) for HSI classification as compared with the results from those state-of-the-art supervised and semi-supervised methods.

关键词： cancer   cervix   Raman spectroscopy   screening  

摘要： The ability to provide quantitative, objective and automated pathological analysis would provide enormous benefits for national cancer screening programmes, in terms of both resource reduction and improved patient wellbeing. The move towards molecular pathology through spectroscopic methods shows great promise, but has been restricted by spectral quality, acquisition times and lack of direct clinical application. In this paper, we present the application of wavelength modulated Raman spectroscopy for the automated label- and fluorescence-free classification of fixed squamous epithelial cells in suspension, such as those produced during a cervical smear test. Direct comparison with standard Raman spectroscopy shows marked improvement of sensitivity and specificity when considering both human papillomavirus (sensitivity +12.0%, specificity +5.3%) and transformation status (sensitivity +10.3%, specificity +11.1%). Studies on the impact of intracellular sampling location and storage effects suggest that wavelength modulated Raman spectroscopy is sufficiently robust to be used in fixed cell classification, but requires further investigations of potential sources of molecular variation in order to improve current clinical tools.

关键词： Games   Instructional quality   Mathematical interactions   Mathematics   Student thinking  

摘要： This study explored the design and implementation of the Cover-up and Un-cover games, two manipulative-based fraction games, in 14 fifth-grade classrooms. We examined how the fraction concepts were integrated into the game design and explored the nature of teacher-student interactions during games using lesson videos. Our examination showed that interactions focused on game progress, rules, and turn taking with little exploration of strategies or the underlying mathematics. To compare the quality of teacher-student interactions during games with interaction quality during other instructional activities, we coded 5 videotaped lessons from each of the 14 classrooms. Statistical results from a dependent t test indicated that teacher-student interactions were of statistically significant lower quality during games than during non-game segments with similar instructional purpose. Teachers might benefit from additional curriculum support and training to implement games as rich mathematical learning opportunities.

关键词： blood specimen   Dengue Fever   Flaviviridae   Aedes   Fourier transform infrared spectroscopy   viruses   Chikungunya Fever   Alphavirus  

摘要： Dengue, zika and chikungunya are arboviruses transmitted by mosquitoes of genus Aedes. In clinical diagnostic routines, cross reactions between dengue and zika may occur because they are viruses of the same family (Flaviviridae);on the other hand, chikungunya is an alphavirus. In this study we suggest the use of FTIR spectroscopy in conjunction with PCA-LDA, SPA-LDA and GA-LDA multivariate classification algorithms as a tool sensitive to biochemical variations caused by the presence of different viruses in the blood. We used 45 blood samples from patients diagnosed with dengue, 30 blood samples from patients diagnosed with zika, 10 samples from patients diagnosed with chikungunya and 45 blood samples from people without these viruses. The objective of the study was to evaluate, mainly, the specificity of the technique in discriminating the blood samples based only on the presence or absence of different viruses and to compare it with some standard diagnostic methods. The results showed sensitivity and specificity values of 100% for the healthy, dengue and chikungunya classes and values close to 90% for zika, suggesting that spectroscopic techniques have great potential for detecting the biochemical variations that the presence of the virus causes in the blood, through a fast methodology.

关键词： 检验机构   特种设备   安全管理   作用  

摘要： 在当今中国经济飞速发展的时代背景下,科学发展速度惊人,科技不断更新改进,各种新型的特种设备被研发、制造并安装,应用在各行各业中。而很多特种设备都具有高危险性,一旦发生安全事故就会造成严重后果,带来不可控的伤害。因此,特种设备检验机构的检验检测工作具有举足轻重的意义。为防止和减少事故的发生、保障人民群众的安全,为特种设备创造安全运行的条件,从而增加使用单位的企业经济效益。本文重点对特种设备检验机构在特种设备安全管理方面起到的作用进行了细致的分析。