检索结果-南通市图书馆

Analysis of mechanical strengths of extreme line casing joint considering geometric, material, and contact nonlinearities

引用

Petroleum Science 2024年第3期21卷 1992-2004页

作者： ji-yun Zhang Chi Peng jian-Hong Fu Quan Cao yu Su jian-yun Pang Zi-Qiang yu Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Engineering Technology Research Institute of CNPC Southwest Oil and Gas Field Company Chengdu610017SichuanChina

To address the challenges associated with difficult casing running,limited annular space,and poor cementing quality in the completion of ultra-deep wells,the extreme line casing offers an effective solution over conventional ***,due to its smaller size,the joint strength of extreme line casing is reduced,which may cause failure when running in the *** address this issue,this study focuses on the CST-ZTΦ139.7 mm×7.72 mm extreme line casing and employs the elastic-plastic mechanics to establish a comprehensive analysis of the casing joint,taking into account the influence of geometric and material nonlinearities.A finite element model is developed to analyze the forces and deformations of the extreme line casing joint under axial tension and external collapse *** model investigates the stress distribution of each thread tooth subjected to various tensile forces and external ***,the tensile strength and crushing strength of the extreme line casing joint are determined through both analytical and experimental *** findings reveal that,under axial tensile load,the bearing surface of each thread tooth experiences uneven stress,with relatively high equivalent stress at the root of each thread *** end thread teeth are valuable spots for *** is observed that the critical fracture axial load of thread decreases linearly with the increase of thread tooth *** external pressure,the circumferential stress is highest at the small end of the external thread,leading to yield *** tensile strength of the joint obtained from the finite element model exhibits a relative error of less than 7%compared to the analytical and experimental values,proving the reliability of the finite element *** tensile strength of the joint is 3091.9 k ***,in terms of anti-collapse capability,the joints demonstrate higher resistance to collapse compared to the casing body,which is consistent with the test resul

关键词： Extreme line casing Elastic-plastic mechanics Finite element analysis Tensile strength Collapse strength

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Berberine alleviates ovarian tissue damage in mice with hepatolenticular degeneration by suppressing ferroptosis and endoplasmic reticulum stress

引用

Journal of Integrative Medicine 2024年第4期22卷 493-502页

作者： Qian-zhuo Liu Hui Han xin-ru Fang Lu-yao Wang Dan Zhao Miao-zhu Yin Nian Zhang Peng-yu jiang Zhi-hui ji Li-min Wu Department of Neurology the First Affiliated Hospital of Anhui University of Chinese MedicineHefei 230031Anhui ProvinceChina Center for Reproduction and Genetics the First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230031Anhui ProvinceChina

Objective:Hepatolenticular degeneration (HLD) is an autosomal recessive disorder that manifests as multiorgan damage due to impaired copper (Cu) metabolism. Female patients with HLD often experience reproductive impairments. This study investigated the protective effect of berberine against ovarian damage in toxic-milk (TX) mice, a murine model for ***:Mice were categorized into control group, HLD TX group (HLD group), penicillamine (Cu chelator)-treated TX group and berberine-treated TX group. Body weight, ovary weight and the number of ovulated eggs were recorded. Follicular morphology and cellular ultrastructure were examined. Total iron, ferrous iron (Fe2+) and trivalent iron (Fe3+) levels, as well as malondialdehyde (MDA), glutathione(GSH) and oxidized glutathione (GSSG), were measured in the ovaries. Western blot analysis was used to analyze the expression of proteins related to ferroptosis and endoplasmic reticulum (ER) ***:Ovarian tissue damage was evident in the HLD group, with a significant increase in ferroptosis and ER stress compared to the control group. This damage was inhibited by treatment with penicillamine,a Cu chelator. Compared with the HLD group, berberine increased the number of ovulations, and improved ovarian morphology and ultrastructure. Further, we found that berberine reduced total iron,Fe2+, MDA and GSSG levels, elevated GSH levels, decreased the expression of the ferroptosis marker protein prostaglandin-endoperoxide synthase 2 (PTGS2), and increased glutathione peroxidase 4 (GPX4)expression. Furthermore, berberine inhibited the expression of ER stress-associated proteins mediated by the protein kinase RNA-like ER kinase (PERK) ***:Ferroptosis and ER stress are involved in Cu-induced ovarian damage in TX mice. Berberine ameliorates ovarian damage in HLD TX mice by inhibiting ferroptosis and ER stress.

关键词： Berberine Hepatolenticular degeneration Copper deposition Ferroptosis Endoplasmic reticulum stress

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Risk assessment of oil and gas investment environment in countries along the Belt and Road Initiative

引用

Petroleum Science 2024年第2期21卷 1429-1443页

作者： Bao-Jun Tang Chang-jing ji yu-Xian Zheng Kang-Ning Liu Yi-Fei Ma Jun-yu Chen Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing100081China School of Management and Economics Beijing Institute of TechnologyBeijing100081China Collaborative Innovation Center of Electric Vehicles in Beijing BeijingChina Sustainable Development Research Institute for Economy and Society of Beijing BeijingChina Institute of Carbon Neutrality ShanghaiTech UniversityShanghai201210China

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM(1,1) model is employed to predict risk values for 2022-2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative.

关键词： Belt and Road Initiative Oil and Gas Investment Risk assessment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

DAIS: a method for identifying spatial domains based on density clustering of spatial omics data

引用

Journal of Genetics and Genomics 2024年第8期51卷 884-887页

作者： Qichao yu Ru Tian xin jin Liang Wu College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China BGI Research ShenzhenGuangdong 518083China BGI ResearchChongqing 401329China BGI Research ShenzhenGuangdong 518083China BGI Research Chongqing 401329China

In multicellular organisms,the spatial arrangement of cells profoundly influences the biological functions of tissues,underscoring the importance of identifying spatial domains in *** advancements in spatial omics,particularly spatial transcriptomics(ST)(Bressan et al.,2023),have enhanced our understanding of tissue spatial organization(Zhang et al.,2022;Tian et al.,2023).

关键词： arrangement identifying domains

来源：

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

Plastid phylogenomics provides new insights into the systematics,diversification,and biogeography of Cymbidium(Orchidaceae)

引用

Plant Diversity 2024年第4期46卷 448-461页

作者： Hai-Yao Chen Zhi-Rong Zhang xin Yao ji-Dong Ya Xiao-Hua jin Lin Wang Lu Lu De-Zhu Li Jun-Bo Yang Wen-Bin yu Center for Integrative Conservation&yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian Elephants Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China University of Chinese Academy of Sciences Huairou DistrictBeijing 101408China Plant Germplasm and Genomics Center Germplasm Bank of Wild SpeciesKunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China State Key Laboratory of Plant Diversity and Specility Crops Institute of BotanyChinese Academy of SciencesHaidian DistrictBeijing 100093China School of Pharmaceutical Sciences Yunnan Key Laboratory of Pharmacology for Natural Productsand Yunnan College of Modern Biomedical IndustryKunming Medical UniversityKunmingYunnan 650500China Southeast Asia Biodiversity Research Institute Chinese Academy of SciencesYezinNay Pyi Taw 05282Myanmar

Cymbidium(Orchidaceae:Epidendroideae),with around 60 species,is widely-distributed across Southeast Asia,providing a nice system for studying the processes that underlie patterns of biodiversity in the ***,phylogenetic relationships of Cymbidium have not been well resolved,hampering investigations of species diversification and the biogeographical history of this *** this study,we construct a plastome phylogeny of 56 Cymbidium species,with four well-resolved major clades,which provides a framework for biogeographical and diversification rate *** dating and biogeographical analyses show that Cymbidium likely originated in the region spanning northern IndoBurma to the eastern Himalayas during the early Miocene(~21.10 Ma).It then rapidly diversified into four major clades in East Asia within approximately a million years during the middle *** *** to the adjacent regions(Borneo,Philippines,and Sulawesi)primarily occurred during the Pliocene-Pleistocene *** analyses indicate that the net diversification rate of Cymbidium has decreased since its origin,and is positively associated with changes in temperature and monsoon *** hydrothermal conditions brought by monsoon intensification in the early Miocene possibly contributed to the initial rapid diversification,after which the net diversification rate was reduced with the cooling climate after the middle *** transition from epiphytic to terrestrial habits may have enabled adaptation to cooler environments and colonization of northern niches,yet without a significant effect on diversification *** study provides new insights into how monsoon activity and temperature changes affected the diversification dynamics of plants in Southeast Asia.

关键词： Cymbidium East Asia Asian monsoons Climate change Biogeographical patterns

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Structural basis of allosteric regulation of ATM kinase

Structural basis of allosteric regulation of ATM kinase

引用

第六届全国冷冻电子显微学与结构生物学专题研讨会

作者： ji-yu xin Zhu XU Xue-juan WANG Zhi-hui ZHANG Gang CAI First Affiliated Hospital of USTC School of Life Sciences University of Science and Technology of China Hefei National Laboratory for Physical Sciences at Microscale and CAS Center for Excellence in Molecular Cell Science Chinese Academy of Sciences

The ATM/Tel1 protein is an apical kinase that orchestrates the multifaceted DNA-damage response, mutations of which are associated with ataxia telangiectasia syndrome. Here we report cryo-EM structures of symmetric dimer (4.1?) and asymmetric dimer (4.3?) of S. cerevisiae Tel1. In the symmetric state, the side chains in Tel1 C-terminal (residues 1,129-2,787) are discernible and an atomic model is built. The substrate binding groove is completely embedded in the symmetric dimer by the intramolecular PRD and intermolecular LID domain, where point

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Effect of micro-Al_(2)O_(3) powders on oxidation and corrosion behaviors of low-carbon MgO-C refractories

引用

Journal of Iron and Steel Research International 2024年第6期31卷 1522-1534页

作者： Yang Chen Zeng-yi Li Hao-bo Tan yu-ran Fu Jun Ding Cheng-ji Deng Chao yu School of Materials Science and Engineering Hunan Institute of TechnologyHengyang 421002HunanChina The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as *** results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock ***,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,***,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature ***,spinel and high-temperature solid solution were formed in the corrosion *** oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.

关键词： Low-carbon MgO-C refractory Oxidation resistance Corrosion resistance Thermal shock resistance Micro-Al_(2)O_(3)powder

来源：

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

Urgent call for attention to diabetes-associated hospital infections

引用

World Journal of Diabetes 2024年第8期15卷 1683-1691页

作者： Xue-Lu yu Li-yun Zhou Xiao Huang xin-yue Li Qing-Qing Pan Ming-Ke Wang ji-Shun Yang Department of Disease Control and Prevention Naval Medical Center of PLANaval Medical UniversityShanghai 200052China Medical Care Center Naval Medical Center of PLANaval Medical UniversityShanghai 200052China

In this editorial,we discuss the recent article by Zhao et al published in the World Journal of Diabetes,which highlights the importance of recognizing the risk indicators associated with diabetes mellitus(DM).Given the severe implications of healthcare-associated infections(HAIs)in hospitalized individuals-such as heightened mortality rates,prolonged hospitalizations,and increased costs-we focus on elucidating the connection between DM and nosocomial *** patients are susceptible to pathogenic bacterial invasion and subsequent infection,with some already harboring co-infections upon ***,DM is an important risk factor for nosocomial urinary tract infections and surgical site infections,which may indirectly affect the occurrence of nosocomial bloodstream infections,especially in patients with DM with poor glycemic *** evidence regarding the impact of DM on healthcare-associated pneumonias remains inconclusive,attention to this potential association is *** patients with DM should prioritize meticulous blood glucose management,adherence to standard operating procedures,hand hygiene practices,environmental disinfection,and rational use of drugs during *** studies are imperative to explore the main risk factors of HAIs in patients with DM,enabling the development of preventative measures and mitigating the occurrence of HAIs in these patients.

关键词： Diabetes mellitus Healthcare-associated infections Nosocomial urinary tract infections Surgical site infections Nosocomial bloodstream infections

来源：

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

Effect of Low-temperature Imidization on Properties and Aggregation Structures of Polyimide Films with Different Rigidity

引用

Chinese Journal of Polymer Science 2024年第8期42卷 1134-1146页

作者： Yan jia Lei Zhai Song Mo Yi Liu Li-xin Liu xin-yu Du Min-Hui He Lin Fan Key Laboratory of Science and Technology on High-tech Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

The traditional high-temperature preparation process of polyimide can cause many problems and limits the wider application in extreme *** important challenge to be solved urgently is the reduction of imidization *** this work,twelve kinds of polyimide films with different chain rigidity were prepared at low temperature of 200℃,in the absence or presence of imidazole used as the *** molecular rigidity and free volume were theoretically calculated,and relationship between structure and properties were systematically *** results show that imidization reaction under low temperatures is significantly affected by the rigidity of molecula r *** rigid structure of polyimide is not conducive to the low-temperature imidization,but this adverse effect can be eliminated by adding catalyst,resulting the notably increased imidization *** optical and thermal properties can be improved to a certain extent for the chemically catalyzed system,resulting in relatively higher heat resistance and thermal *** the mechanical performance could be determined by com plicating factors,greatly different from polyimide films prepa red by high temperature *** investigate aggregation structures of film s,the effect of chain rigidity and catalyst on the stacking or orientation of molecular chains was further *** wo rk can contribute to the understanding of chemically catalyzed imidization that is rarely reported in the existing research,and will provide guidance for the low-temperature preparation of high-performance polyimides.

关键词： Polyimide Imidization Catalyst Structure and properties Aggregation structures

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nonalternant isomer of pentacene fusing two azulene units

引用

Chinese Chemical Letters 2024年第5期35卷 244-248页

作者： Bo yu Pengchen Du jianwen Guo Hanshen xin jianhua Zhang Department of Chemistry College of SciencesShanghai UniversityShanghai 200444China School of Microelectronics Shanghai UniversityShanghai 201800China

Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1/2/3. Az-PH1 was initially developed through the rhodium(Ⅱ)-catalyzed cyclization of bis(N-tosylhydrazone)s. Intriguingly, Az-PH1 was also unexpectedly obtained during a nickel(0)-catalyzed one-step tandem reaction. We investigated the optical and electrochemical properties, aromaticity, and photo-oxidative stability of Az-PH1, comparing it with the well-known pentacene using density functional theory, electrochemical, and photophysical tests. Our results showed that the azulene-fusing strategy resulted in a molecule with narrow optical bandgaps(2.046 eV) and a long half-life time under ambient air conditions.

关键词： Azulene Isomer Polycyclic aromatic hydrocarbon Nickel(0)-catalyzed Photo-oxidative stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：