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一种基于T-分布随机近邻嵌入的聚类集成方法

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电子与信息学报 2018年第6期40卷 1316-1322页

作者：徐森花小朋徐静徐秀芳皋军安晶盐城工学院信息工程学院盐城224051

该文将T-分布随机近邻嵌入(TSNE)引入到聚类集成问题中,提出一种基于TSNE的聚类集成方法。首先通过TSNE最小化超图邻接矩阵的行对应的高维数据点与低维映射点分布之间的KL散度,使得高维空间结构在低维空间得以保持,然后在低维空间运行... 详细信息

该文将T-分布随机近邻嵌入(TSNE)引入到聚类集成问题中,提出一种基于TSNE的聚类集成方法。首先通过TSNE最小化超图邻接矩阵的行对应的高维数据点与低维映射点分布之间的KL散度,使得高维空间结构在低维空间得以保持,然后在低维空间运行层次聚类算法获得最终的聚类结果。在基准数据集上的实验结果表明:TSNE能够提高层次聚类算法的聚类质量,该文方法获得了优于主流聚类集成方法的结果。

关键词：机器学习聚类分析聚类集成层次聚类

A single tube modified allele-specific-PCR for rapid detection of erythromycin-resistant Mycoplasma pneumoniae in Beijing

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Chinese Medical Journal 2012年第15期125卷 2671-2676页

作者： LI Shao-li SUN Hong-mei ZHAO Han-qing cao Ling YUAN Yi FENG Yan-ling XUE Guan-hua Department of Bacteriology Capital Institute of Pediatrics Beijing100020 China Affiliated Children's Hospital of Capital Institute of Pediatrics Beijing 100020 China

Background Mycoplasma pneumoniae （M. pneumoniae） is one of the common pathogens causing atypical pneumonia. In recent years, resistance to macrolides has become more common, especially in China. Previous studies have confirmed that the mutation at position 2063 in domain V of the 23S rRNA is the most prevalent, followed by the mutation at position 2064. Reported molecular detection methods for the identification of these mutations include direct sequencing, restriction fragment length polymorphism analysis, real-time polymerase chain reaction （PCR） with high-resolution melt analysis, and nested PCR-linked with capillary electrophoresis, etc. The most commonly used method for monitoring resistance-conferring mutations in M. pneumoniae is direct DNA sequencing of PCR or nested PCR products. However, these methods are time-consuming, labor-intensive or need expensive equipments. Therefore the development of rapid and sensitive methods is very important for monitoring the resistance globally. Methods In this study, we reported a fast and cost-effective method for detecting 2063 and/or 2064 macrolide resistant mutations from specimens using a modified allele-specific PCR analysis, and all results were compared with the sequencing data. We also analyzed the clinical courses of these samples to confirm the modified allele-specific PCR results. Results Among 97 M. pneumoniae specimens, 88 were found to possess mutations by this method, and all modified allele-specific PCR analysis results were consistent with the sequencing data. The data of the clinical courses of these 97 cases showed that they suffered from severe pneumonia. Erythromycin showed better efficacy on cases from which no macrolide resistance mutation was found on their specimens. However, in some cases from which mutations were detected, erythromycin monotherapy had poor efficacy, and on these patients severe symptoms improved only when azithromycin was added to the treatment. Conclusions The drug-resistant M

关键词： mycoplasma pneumoniae erythromycin resistance, allele-specific PCR

Clathrin-dependent endocytosis predominantly mediates protein absorption by fat body from the hemolymph in Bombyx mori

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Insect Science 2020年第4期27卷 675-686页

作者： Yu-Jie Wang Shu-Yan Li Jia-Ye Zhao Kang Li jing Xu Xian-Ying Xu Wen-Mei Wu Rong Yang Yang Xiao Ming-Qiang Ye Ji-Ping Liu Yang-Jin Zhong Yang cao Hui-Yu Yi Ling Tian Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center College of Animal ScienceSouth China Agricultural UniversityGuangzhouChina Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology Institute of Insect Science and TechnologySchool of Life SciencesSouth China Normal UniversityGuangzhouChina The Sericultural and Agri-Food Research Institute of the Guangdong Academy of Agricultural Sciences GuangzhouChina

During insect larval-pupal metamorphosis,proteins in the hemolymph are absorbed by the fat body for the maintenance of intracellular homeostasis;however,the type of proteins and how these proteins are internalized into the fat body are *** Bombyx mori,the developmental profiles o f total proteins in the hemolymph and fat body showed that hemolymph-decreased protein bands(55-100 kDa)were in accordance with those protein bands that increased in the fat *** o f clathrin-dependent endocytosis predominantly blocked the transportation o f 55-100 kDa proteins from the hemolymph into the fat body,which was further verified by RNA interference treatment o f *** hexamerins were shown to comprise〜90%of the total identified proteins in both the hemolymph and fat body by mass spectrum(MS)*** addition,hemolymphspecific proteins were mainly involved in material transportation,while fat body-specific proteins particularly participated in *** this paper,four hexamerins were found for the first time,and potential proteins absorbed by the fat body from the hemolymph through clathrin-dependent endocytosis were *** study sheds light on the protein absorption mechanism during insect metamorphosis.

关键词： Bombyx mori clathrin-mediated endocytosis fat body hemolymph uptake of proteins

分数阶微分方程多点边值问题正解的存在唯一性

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北京工业大学学报 2015年第8期41卷 1275-1280页

作者：谭静静程曹宗北京工业大学应用数理学院北京100124

为了研究分数阶微分方程多点边值问题解的存在唯一性,主要利用和算子的不动点定理以及格林函数的性质,得到一类分数阶微分方程多点边值问题正解的存在唯一性,并且通过构造迭代序列来逼近此正解的结果,进而得出对此类边值问题正解的估计... 详细信息

为了研究分数阶微分方程多点边值问题解的存在唯一性,主要利用和算子的不动点定理以及格林函数的性质,得到一类分数阶微分方程多点边值问题正解的存在唯一性,并且通过构造迭代序列来逼近此正解的结果,进而得出对此类边值问题正解的估计结论.作为应用,最后给出了一个例子.

关键词：分数阶微分方程边值问题不动点定理

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模卡式拼装节能墙体的保温性能

东北大学学报（自然科学版） 2007年第6期28卷 871-874页

作者：曹国华朱浮声董锋东北大学资源与土木工程学院辽宁沈阳110004

模卡式拼装节能墙体采用条形榫卯砌块拼装式施工方法,可以拼装成各种尺寸的内隔墙和非承重墙.将其看成两向非均质围护结构计算其平均热阻,利用平壁稳定传热的基本理论计算其传热系数,最后对其保温层的经济厚度进行了讨论.计算分析表明,... 详细信息

模卡式拼装节能墙体采用条形榫卯砌块拼装式施工方法,可以拼装成各种尺寸的内隔墙和非承重墙.将其看成两向非均质围护结构计算其平均热阻,利用平壁稳定传热的基本理论计算其传热系数,最后对其保温层的经济厚度进行了讨论.计算分析表明,模卡式拼装节能墙体传热系数仅为0.689 W/(m2.K),远低于其他常用墙体,具有良好的节能效果.墙体的聚苯板厚度采用0.08 m时,能取得最佳经济指标,墙体的传热系数仅为0.400 W/(m2.K).

关键词：节能建筑模卡式拼装节能墙体传热阻经济厚度传热系数

Binary Star Fractions from the LAMOST DR4

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Research in Astronomy and Astrophysics 2018年第5期18卷 47-58页

作者： Zhi-Jia Tian Xiao-Wei Liu Hai-Bo Yuan Bing-Qiu Chen Mao-Sheng Xiang Yang huang Chun Wang hua-Wei Zhang Jin-Cheng Guo Juan-Juan Ren Zhi-Ying Huo Yong Yang Meng Zhang Shao-Lan Bi Wu-Ming Yang Kang Liu Xian-Fei Zhang Tan-Da Li Ya-Qian Wu jing-hua Zhang Department of Astronomy Peking University Beijing 100871 China Department of Astronomy Beijing Normal University Beijing 100875 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China Department of Astronomy Yunnan University Kunming 650091 China

Stellar systems composed of single, double, triple or higher-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through comparing the radial velocity variations from multiepoch observations, we analyze the binary fraction of dwarf stars observed with LAMOST. Effects of different model assumptions, such as orbital period distributions on the estimate of binary fractions,are investigated. The results based on log-normal distribution of orbital periods reproduce the previous complete analyses better than the power-law distribution. We find that the binary fraction increases with Teff and decreases with [Fe/H]. We first investigate the relation between α-elements and binary fraction in such a large sample as provided by LAMOST. The old stars with high [α/Fe] dominate with a higher binary fraction than young stars with low [α/Fe]. At the same mass, earlier forming stars possess a higher binary fraction than newly forming ones, which may be related with evolution of the Galaxy.

关键词： binaries general- binaries spectroscopic - Galaxy stellar content - stars statistics- surveys

Effects of Different Concentrations of Homologous Probiotics on Small Intestinal Structure of 21-day-old Broilers

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Animal Husbandry and Feed Science 2015年第5期7卷 294-297页

作者： Zhang Yuxian Wang Wenli Wang Jinqiu cao jing Chen Yaoxing Wang Zixu Beijing Vocational College of Agriculture Animal Husbandry College of Veterinary Medicine China Agricultural University

This test was conducted to study the effects of different doses of homologous probiotics on intestinal mucosa structure of 21-day-old broilers. A total of 1 500 one-day-old AA broilers with similar weight were randomly divided into five groups, with 10 replicates in each group and 30 broilers （ half males and half fe- males） in each replicate. The broilers were fed with the diets containing five kinds of different doses of homologous probiotics. The broilers ate and drank freely during the test. The test lasted for 21 days. Histological and histochemical methods were taken to measure villi length, mucosal thickness, wall thickness and the ratio of villi length to crypt depth （V/C） of duodenum, jejunum and ileum of the 21-day-old broilers. The results showed that, the effects of 0.3% homologous probiotics on the intestinal mucosal stroctrue of 21-day-old broilers were the best, and values of villi length, V/C, mucosal thickness and intestinal wall thickness in the O. 3% homologous probiotics group reached the maximum. The effects on improving and enhancing the digestion and absorption of the broiler small intestine in the 0.3% homologous probiotics group were the best.

关键词： Broilers Homologous probiotics Small intestine mucosal structure

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电力变压器铁心的非线性磁化特性

高电压技术 2010年第10期36卷 2582-2587页

作者：黄晶晶徐习东曾平马丰华广东电网公司广州供电局广州510620 浙江大学电气工程学院杭州310027 华东电力试验研究院上海200437

电磁暂态仿真是电气设备设计、绝缘等级研究和继电保护的基础。在计算机上进行这些研究,需要提供各种元件的仿真数字模型。变压器及其相关模型的建立对励磁涌流、磁滞、谐波和分次谐波的研究尤其重要,且变压器铁心的非线性特性又是变压... 详细信息

电磁暂态仿真是电气设备设计、绝缘等级研究和继电保护的基础。在计算机上进行这些研究,需要提供各种元件的仿真数字模型。变压器及其相关模型的建立对励磁涌流、磁滞、谐波和分次谐波的研究尤其重要,且变压器铁心的非线性特性又是变压器建模的关键。为此,从考虑铁心损耗的空载单相变压器模型出发,根据变压器励磁磁链与磁化电流的关系将基本磁化曲线分段线性化,运用迭代的方法求得每个分段下磁链的最大值。利用分段电压峰值与对应分段的等效电阻的关系,求得了该分段磁链与磁化电流曲线的斜率。根据求得的每个分段磁链的最大值及该线性化分段的斜率,从而较为精确地求得了磁链与磁化电流的关系曲线。分段数N可根据精度的需要选取。该方法充分利用了已知的变压器励磁电压电流关系和空载实验的各种数据,直观简洁,并可以根据需要调节计算精度。仿真验证了该方法的正确性和有效性。

关键词：电力变压器继电保护磁化曲线励磁涌流分段线性化电磁暂态仿真

Adjusting Na doping via wet-chemical synthesis to enhance thermoelectric properties of polycrystalline SnS

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Science China Materials 2019年第7期62卷 1005-1012页

作者： huaichao Tang Jin-Feng Dong Fu-hua Sun Pengpeng Shang jing-Feng Li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China College of Chemistry and Materials Science Shandong Agricultural University Taian 271018 China

Tin sulfide (SnS) has analogous structural features to tin selenide (SnSe), but contains more abundant resources as compared with SnSe. SnS has elicited attention as a potential eco-friendly therm oelectric (TE) material. However, the intrinsic carrier concentration of SnS is very low, thereby hindering the performance improvement of the material. This study proposes that the TE properties of polycrystalline Nadoped SnS (synthesized through an improved chemical coprecipitation) can be significantly enhanced. The maximum power factor (PF) of 362 μW m^-1K^-2 at 873 K was achieved, presenting a state-of-the-art value for the polycrystalline SnS. Considering the merits of the improved electrical properties and lower thermal conductivity of SnS, the highest ZT was up to 0.52 at 873 K even without intentional chemical doping. This study offers an effective approach for improving the PF to achieve high ZT in SnS. Hence, we expect that this new perspective can be extended to other dopants and broaden the scope of synthesis technology.

关键词： SnS rapid preparation Na doping therm oelectric