检索结果-南通市图书馆

The Impact of Climate Change on Country’s Fragility Assessment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Applied Mathematics and Physics 2020年第11期8卷 2447-2462页

作者： Mengmeng Li dongsheng bi Dongfeng Yang Key Laboratory of Land Environment and Disaster Monitoring MNR China University of Mining and Technology Xuzhou China School of Environment Science and Spatial Informatics China University of Mining and Technology Xuzhou China Department of Electronic Engineering Fudan University Shanghai China Department of Electronic Engineering Northeast Petroleum University Daqing China

The damage costs of climate change have the potential to cause the breakdown of governmental structures. The paper focuses on how climate change impacts the state’s fragility and how the government should intervene. The paper chooses temperature and rainfall as climate change indicators and establishes a comprehensive evaluating model. The weighting method of the model is determined by combining coefficient of variation method and improved entropy method. The model will output the objective comprehensive evaluation of state’s fragility. The state’s fragilities are quantitatively divided into three levels consisting of the fragile, the vulnerable and the stable in the model. For validation, this paper selects six representative countries and analyzes the degree and the approach of climate change’s impacts on state’s fragility. The fragile values by the model are consistent with the situation in these countries. The state’s fragilities are also predicted by back propagation (BP) neural network. This paper analyzes the impacts of human interventions on improving state’s fragility. The results indicate that the paper could provide reasonable suggestions for the government in the aspects of when and how to take what kind of interventions to improve state’s fragility.

关键词： State’s Fragility Climate Change Comprehensive Evaluating Model Objective Weighting Model

Assessment of cortical bone fatigue using coded nonlinear ultrasound

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第9期30卷 274-283页

作者： Duwei Liu Boyi Li dongsheng bi Tho N.H.T.Tran Yifang Li Dan Liu Ying Li Dean Ta Center for biomedical Engineering School of Information Science and TechnologyFudan UniversityShanghai 200433China Academy for Engineering and Technology Fudan UniversityShanghai 200433China Human Phenome Institute Fudan UniversityShanghai 200433China

Bone fatigue accumulation is a factor leading to bone fracture,which is a progressive process of microdamage deteriorating under long-term and repeated *** the microdamage of the early stage in bone is difficult to be investigated by linear ultrasound,the second harmonic generation method in nonlinear ultrasound technique is employed in this paper,which is proved to be more sensitive to *** solve the deficiency that the second harmonic component is easily submerged by noise in traditional nonlinear measurement,a weighted chirp coded sinusoidal signal was applied as the ultrasonic excitation,while pulse inversion is implemented at the receiving *** effectiveness of this combination to improve the signal-to-noise ratio has been demonstrated by in vitro *** fatigue loading experiments were conducted on the cortical bone plate in vitro for microdamage *** was a significant increase in the slope of the acoustic nonlinearity parameter with the propagation distance(increased by 8%and 24%respectively)when the bone specimen was at a progressive level of *** results indicate that the coded nonlinear ultrasonic method might have the potential in diagnosing bone fatigue.

关键词： nonlinear ultrasonic Lamb wave bone fatigue chirp code pulse inversion

Amplitude modulation excitation for cancellous bone evaluation using a portable ultrasonic backscatter instrumentation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第11期31卷 106-114页

作者： Boyi Li Chengcheng Liu Xin Liu Tho N.H.T.Tran Ying Li Dan Li dongsheng bi Duwei Liu Dean Ta Academy for Engineering and Technology Fudan UniversityShanghai 200433China The Center for biomedical Engineering Fudan UniversityShanghai 200433China The State Key Laboratory of Medical Neurobiology Fudan UniversityShanghai 200433China

The ultrasonic backscatter(UB)has the advantage of non-invasively obtaining bone density and structure,expected to be an assessment tool for early diagnosis *** former UB measurements were based on exciting a short single-pulse and analyzing the ultrasonic signals backscattered in *** study aims to examine amplitude modulation(AM)ultrasonic excitation with UB measurements for predicting bone *** AM multiple lengths excitation and backscatter measurement(AM-UB)functions were integrated into a portable ultrasonic instrument for bone *** apparent integrated backscatter coefficient in the AM excitation(AIB_(AM))was evaluated on the AM-UB *** correlation coefficients of the AIB_(AM) estimating volume fraction(BV/TV),structure model index(SMI),and bone mineral density(BMD)were then *** correlations(|R|=0.82-0.93,pbit more stability both in 1.0-MHz and 3.5-MHz *** recommendations in AM-UB measurement were that the avoided length(T1)should be lower than AM excitation length,and the analysis length(T2)should be enough long but not more than AM excitation *** authors conducted an AM-UB measurement for cancellous bone *** the AM excitation length could substantially enhance AIB_(AM) values stability with varying analyzed *** study suggests the portable AM-UB instrument with the integration of real-time analytics software that might provide a potential tool for osteoporosis early screening.

关键词： ultrasonic backscatter measurement amplitude modulation osteoporosis bone diagnosis

基于双特征的丘陵山区耕地低空遥感图像配准算法

在线全文

学校读者我要写书评

暂无评论

北京航空航天大学学报 2018年第9期44卷 1952-1963页

作者：宋飞杨扬杨昆张愫毕东升云南师范大学信息学院昆明650500 西部资源环境地理信息技术教育部工程研究中心昆明650500 云南师范大学模式识别与人工智能实验室昆明650500

针对丘陵山区耕地小型无人机航拍图像(低空遥感图像)中的尺度变化、几何畸变、图像重叠等问题,提出了基于双特征的丘陵山区耕地低空遥感图像配准算法。该算法鉴于丘陵山区耕地背景环境复杂、光照因素等影响,采用尺度不变特征SURF算法提... 详细信息

针对丘陵山区耕地小型无人机航拍图像(低空遥感图像)中的尺度变化、几何畸变、图像重叠等问题,提出了基于双特征的丘陵山区耕地低空遥感图像配准算法。该算法鉴于丘陵山区耕地背景环境复杂、光照因素等影响,采用尺度不变特征SURF算法提取了遥感图像的特征点,并构建了能够稳健描述航拍图像几何特征的双特征描述子;在此基础上,以高斯混合模型(GMM)为核心,结合2个单一特征差异描述子(基于欧氏距离的全局特征和基于和向量的局部特征)构造的双特征描述子,得到了能够同时通过2种特征进行对应关系评估的双特征有限混合模型(DFMM),并通过再生核希尔伯特空间(RKHS),基于高斯径向基函数(GRBF)对待配准图像进行了全局与局部结构双约束的空间变换更新。为了验证本文算法的可行性及其性能,采用小型无人机航拍的丘陵山区坡耕地多视角遥感图像开展了实验,将本文算法与SIFT、SURF、CPD、AGMReg、GLMDTPS及PRGLS进行了比较。实验结果表明,本文算法不仅在不同坡度的坡耕地航拍图像多视角配准过程中,均具有较好的鲁棒性,也适用于部分复杂地形小型无人机航拍的多视角遥感图像配准。

关键词：图像配准小型无人机双特征有限混合模型再生核希尔伯特空间(RKHS)

在线全文

学校读者我要写书评

暂无评论

全面提升黄河防凌减灾综合能力的对策与建议

中国水利 2009年第9期 14-15页

作者：蔡彬张希玉毕东升水利部黄河水利委员会防汛办公室郑州450003

每年12月至次年3月，黄河上游、中游及下游均发生凌汛，是我国凌汛成灾最为严重的河流。在宁夏至内蒙古河段（以下简称宁蒙河段）、河南至山东河段为低纬度流向高纬度，河流封冻时下段早于上段，解冻时下段晚于上段，而且冰盖厚度下厚... 详细信息

每年12月至次年3月，黄河上游、中游及下游均发生凌汛，是我国凌汛成灾最为严重的河流。在宁夏至内蒙古河段（以下简称宁蒙河段）、河南至山东河段为低纬度流向高纬度，河流封冻时下段早于上段，解冻时下段晚于上段，而且冰盖厚度下厚上薄，封、开河时容易形成冰凌卡塞和冰坝壅水引发堤防决口等凌汛灾害，危及局部滩区群众生命财产安全。黄河防凌工作已成为我国冬春季防汛工作的头等大事。

关键词：对策建议防凌减灾提升黄河

Visualizing extended defects at the atomic level in a bi_(2)Sr_(2)CaCu_(2)O8_(+σ) superconducting wire

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第9期33卷 43-47页

作者： Kejun Hu Shuai Wang Boyu Li Ying Liu binghui Ge dongsheng Song Information Materials and Intelligent Sensing Laboratory of Anhui Province Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationInstitutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China

The microstructure significantly influences the superconducting ***,the defect structures and atomic arrangements in high-temperature bi_(2)Sr_(2)CaCu_(2)O8_(+σ) superconducting wire are directly characterized via stateof-the-art scanning transmission electron *** oxygen atoms are observed in both the charge reservoir layers and grain boundaries in the doped *** phases with varied numbers of CuO_(2) layers are found,and twist interfaces with different angles are *** study provides insights into the structures of bi-2212 wire and lays the groundwork for guiding the design of microstructures and optimizing the production methods to enhance superconducting performance.

关键词： superconductor microstructure defect scanning transmission electron microscopy

Disinfection byproduct precursor removal by enhanced coagulation and their distribution in chemical fractions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第11期25卷 2207-2213页

作者： Yanmei Zhao Feng Xiao dongsheng Wang Mingquan Yan Zhe bi Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Environmental Engineering Peking University

Raw water from the Songhua River was treated by four types of coagulants, ferric chloride （FeC13）, aluminum sulfate （A12（504）3）, polyaluminum chloride （PACl） and composite polyaluminum （HPAC）, in order to remove dissolved organic matter （DOM）. Considering the disinfection byproduct （DBP） precursor treatability, DOM was divided into five chemical fractions based on resin adsorption. Trihalomethane formation potential （THMFP） and haloacetic acid formation potential （HAAFP） were measured for each fraction. The results showed that hydrophobic acids （HoA）, hydrophilic matter （HIM） and hydrophobic neutral （HoN） were the dominant fractions. Although both HoN and HoA were the main THM precursors, the contribution for THMFP changed after coagulation. Additionally, HoA and HiM were the main HAA precursors, while the contribution of HoN to HAAFP significantly increased after coagulation. HoM was more easily removed than HiM, no matter which coagulant was used, especially under enhanced coagulation conditions. DOC removal was highest for enhanced coagulation using FeCl3 while DBPFP was lowest using PAC1. This could indicate that not all DOC fractions contained the precursors of DBPs. Reduction of THMFP and HAAFP by PAC1 under enhanced coagulation could reach 51% and 59% respectively.

关键词： trihalomethanes haloacetic acids dissolved organic matter chemical fractionation enhanced coagulation

Rapid repair techniques for severely earthquake-damaged circular bridge piers with flexural failure mode

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2017年第2期16卷 415-433页

作者： Sun Zhiguo Li Hongnan bi Kaiming Si bingjun Wang dongsheng Department of Disaster Prevention Engineering Institute of Disaster Prevention Faculty of Infrastructure Engineering Dalian University of Technology Centre for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin University Institute of Road and Bridge Engineering Dalian Maritime University

In this study, three rapid repair techniques are proposed to retrofit circular bridge piers that are severely damaged by the flexural failure mode in major earthquakes. The quasi-static tests on three 1：2.5 scaled circular pier specimens are conducted to evaluate the efficiency of the proposed repair techniques. For the purpose of rapid repair, the repair procedure for all the specimens is conducted within four days, and the behavior of the repaired specimens is evaluated and compared with the original ones. A finite element model is developed to predict the cyclic behavior of the repaired specimens and the numerical results are compared with the test data. It is found that all the repaired specimens exhibit similar or larger lateral strength and deformation capacity than the original ones. The initial lateral stiffness of all the repaired specimens is lower than that of the original ones, while they show a higher lateral stiffness at the later stage of the test. No noticeable difference is observed for the energy dissipation capacity between the original and repaired pier specimens. It is suggested that the repair technique using the early-strength concrete jacket confined by carbon fiber reinforced polymer （CFRP） sheets can be an optimal method for the rapid repair of severely earthquake-damaged circular bridge piers with flexural failure mode.

关键词： rapid repair severely earthquake-damaged circular bridge piers flexural failure mode CFRP early-strengthconcrete

基于对癌细胞作用的人参与黄芪的药性异同点的分子机制研究

在线全文

学校读者我要写书评

暂无评论

北京中医药大学学报 2024年第2期47卷 199-212页

作者：潘成学张芳平张奇李文王献丽娄舒奇许东升毕跃峰郑州大学药学院郑州450001

目的比较人参、黄芪对不同癌细胞的作用,探讨二者药性异同的分子机制。方法CCK-8法检测质量浓度梯度的人参标准提取物(RSE75)、黄芪标准提取物(HQE75)对不同癌细胞(人源肝癌细胞Hep G2、鼠源肝癌细胞H22、人源肺癌细胞H1299、人源肺癌细... 详细信息

目的比较人参、黄芪对不同癌细胞的作用,探讨二者药性异同的分子机制。方法CCK-8法检测质量浓度梯度的人参标准提取物(RSE75)、黄芪标准提取物(HQE75)对不同癌细胞(人源肝癌细胞Hep G2、鼠源肝癌细胞H22、人源肺癌细胞H1299、人源肺癌细胞A549、人源食管癌细胞EC109及鼠源食管癌细胞AKR)增殖活性的影响;RT⁃qPCR法检测RSE75、HQE75对白细胞介素-6(IL⁃6)、肿瘤坏死因子α(TNF⁃α)、转化生长因子-β(TGF⁃β)mRNA表达及A549细胞中DNA甲基转移酶(DNMTs)/10-11易位甲基胞嘧啶双加氧酶2(TET2)平衡关系的影响;利用克隆形成实验、Annexin V⁃FITC/PI染色技术、流式细胞仪分别检测RSE75、HQE75对A549细胞克隆形成率、凋亡水平、周期变化的影响;转录组测序技术探索RSE75及HQE75治疗肺癌的潜在靶点和作用途径。结果与空白对照组比较,RSE75组癌细胞存活率均降低,多数HQE75组差异无统计学意义;RSE75组及HQE75组IL⁃6、TNF⁃α和TGF⁃βmRNA表达水平均降低;RSE75可抑制A549细胞的克隆形成率,且随剂量增加抑制率降低,而HQE75无明显抑制作用;RSE75及HQE75均可诱导A549细胞凋亡,并将DNA复制阻滞在G1/S期,相同质量浓度下,RSE75的诱导凋亡作用强于HQE75;RSE75组DNMTs mRNA表达水平降低、TET2 mRNA表达水平升高,HQE75组DNMTs、TET2 mRNA表达水平均降低。RNA测序研究结果表明,RSE75与HQE75有着共同作用靶点与作用途径,共同作用靶点主要有白细胞介素-8、趋化因子配体1、细胞间黏附分子-1、趋化因子配体2等,共同作用途径主要有白细胞介素-17、核转录因子-κB、肿瘤坏死因子信号通路等,多为免疫调节途径;不同点在于,人参能够通过血管内皮生长因子A、早期生长应答因子1等靶点作用于缺氧诱导因子-1信号通路等抑制癌细胞增殖,黄芪能够通过IL⁃6、核转录因子等靶点调控氨基酸代谢、核苷酸结合寡聚化结构域样受体信号通路等发挥免疫调节作用。结论人参与黄芪都具有明显的免疫调节作用,同时,人参还具有明显的抑制癌细胞增殖作用;人参能调节DNMTs/TET2平衡,而黄芪主要抑制DNMTs表达。本研究从分子水平上阐明了二者在抗癌作用上药性的不同,为同为补气药的人参和黄芪的临床应用提供了科学依据,也为中药药性对比分子机制研究提供了思路。

关键词：人参黄芪抗癌药性对比 DNA甲基转移酶转录组测序分子机制