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王利民,徐世,任传波
《中国工程科学》 2007年 第9卷 第2期 页码 30-35
在混凝土类软化材料断裂研究中,裂纹端部损伤区被简化为具有黏聚应力分布的非线性裂纹,该黏 聚力对裂纹扩展有阻抗作用。裂纹体的应力强度因子是断裂力学标志载荷作用与几何构型因素的量化表达指标; 黏聚力形成的阻抗强度因子数值,与黏聚裂纹长度和材料极值拉伸应力存在数量关系。通过双K断裂判据,以 带切口的三点弯曲梁为断裂力学模型,分析了裂纹黏聚阻力对断裂过程的影响规律,计算该弯曲梁结构断裂试 样的最大承担载荷;其结果比较符合实验数据。
一种基于锚点的谱聚类方法 None
Qin ZHANG, Guo-qiang ZHONG, Jun-yu DONG
《信息与电子工程前沿(英文)》 2018年 第19卷 第11期 页码 1385-1396 doi: 10.1631/FITEE.1700262
关键词: 聚类;谱聚类;图拉普拉斯;锚点
莫茜,罗毅
《中国工程科学》 2008年 第10卷 第11期 页码 65-68
徐世烺,王利民
《中国工程科学》 2002年 第4卷 第5期 页码 53-58
混凝土裂缝端部断裂过程区的粘聚力分布是导致混凝土断裂呈现非线性特性的重要原因。基于混凝土的断裂特性和虚拟裂缝端部存在粘聚力的分析模型,并通过分布函数的特性分析,提出了粘聚力分布函数的两种简化表达式:一为单参数待定式,另一为双参数待定式。进而通过裂缝张开位移实测数据即可求得粘聚力分布,并且给出了适当的算例分析和讨论。
地震波荷载作用下类岩石试样波形传播和裂纹扩展数值模拟研究 Article
张晓平, 张旗, 刘泉声, 肖锐铧
《工程(英文)》 2022年 第17卷 第10期 页码 140-150 doi: 10.1016/j.eng.2021.09.023
曾黄麟,袁慧,刘小芳
《中国工程科学》 2004年 第6卷 第11期 页码 33-37
基于一个约束条件下的非线性规划问题的优化计算思想,把模糊中心聚类中计算输入矢量与中心的距离来实现聚类作为一种优化计算问题,证明了模糊中心聚类方法,取一个适当的属函数,其聚类中心vi为模糊聚类中心价值函数的极小值,推导出了基于模糊中心聚类的模式识别的无导师递推学习方法,提出了模糊中心聚类模式分类神经网络结构,该网络可以实现并行数据处理和模式分类的软划分和硬划分。
基于GPU的密度峰值并行聚类算法 Article
Ke-shi GE, Hua-you SU, Dong-sheng LI, Xi-cheng LU
《信息与电子工程前沿(英文)》 2017年 第18卷 第7期 页码 915-927 doi: 10.1631/FITEE.1601786
关键词: GPU;密度峰值;聚类;并行计算
基于同一健康策略探究老挝人、动物和环境中多黏菌素耐药性的传播特征 Article
周宇晴, Refath Farzana, Somsavanh Sihalath, Sayaphet Rattanavong, Manivanh Vongsouvath, Mayfong Mayxay, Kirsty Sands, Paul N. Newton, David A.B. Dance, Brekhna Hassan, Timothy R. Walsh
《工程(英文)》 2022年 第15卷 第8期 页码 45-56 doi: 10.1016/j.eng.2022.01.013
This study was designed to investigate the molecular epidemiology of mobile colistin resistance (mcr) using a "One-Health" approach in Laos and to predict whether any dominant plasmid backbone and/or strain type influences the dissemination of mcr. We collected 673 samples from humans (rectal normal flora), poultry, and the environment (water, flies, birds, etc.) in Vientiane, Lao People's Democratic Republic (Laos), from May to September 2018. A total of 238 Escherichia coli (E. coli) isolated from nonduplicative samples, consisting of 98 MCR-positive E. coli (MCRPEC) ("mcr" denotes the gene encoding mobile colistin resistance, and "MCR" denotes the subsequent protein encoded by mcr) and 140 MCRnegative E. coli (MCRNEC), were characterized by phenotype and Illumina sequencing. A subset of MCRPEC was selected for MinION sequencing, conjugation assay, plasmid stability, and growth kinetics in vitro. The prevalence of MCRPEC was found to be 14.6% (98/673), with the highest prevalence in human rectal swabs (45.9% (45/98), p < 0.0001, odds ratio (OR): 0.125, 95% confidence interval (CI): 0.077–0.202). The percentages of MCRPEC from other samples were 14.3% (2/14) in dog feces, 12.0% (24/200) in flies, 11.0% (11/100) in chicken meat, 8.9% (8/90) in chicken cloacal, 8.0% (4/50) in chicken caeca, and 7.5% (4/53) in wastewater. MCRPEC was significantly more resistant to co-amoxiclav, sulfamethoxazoletrimethoprim, levofloxacin, ciprofloxacin, and gentamicin than MCRNEC (p < 0.05). Genomic analysis revealed the distribution of MCRPEC among diverse clonal types. The putative plasmid Inc types associated with mcr-1 were IncX4, IncHI2, IncP1, IncI2, and IncFIA, and those associated with mcr-3 were IncFII, IncFIA, IncFIB, IncP1, and IncR. Recovery of highly similar plasmids from both flies and other sampling sectors implied the role of flies in the dissemination of mcr-1. mcr-positive plasmids were shown to be conjugative, and a significantly high transfer rate into a hypervirulent clone ST1193 was observed. Plasmids containing mcr irrespective of Inc type were highly stable and invariably did not exert a fitness effect upon introduction into a new host. These findings signify the urgent need for a standard infection control program to radically decontaminate the source of resistance.
容易断裂的可降解塑料 Letter
杨栩旭, Jason Steck, 杨加伟, 王叶成, 锁志刚
《工程(英文)》 2021年 第7卷 第5期 页码 624-629 doi: 10.1016/j.eng.2021.02.009
标题 作者 时间 类型 操作
基于同一健康策略探究老挝人、动物和环境中多黏菌素耐药性的传播特征
周宇晴, Refath Farzana, Somsavanh Sihalath, Sayaphet Rattanavong, Manivanh Vongsouvath, Mayfong Mayxay, Kirsty Sands, Paul N. Newton, David A.B. Dance, Brekhna Hassan, Timothy R. Walsh
期刊论文